So what happens when you reach LA? Is this a round trip?

Maine to LA is about 48 hours of driving by the shortest route. You'll have to add some more time to that because you want to take a more southern route. So realistically, it will take you 5 days to get there so you will have little chance to stop on the way out for sightseeing.

That's assuming you don't run into bad weather, even the South can have ice storms that screw up travel.

I would have several routes mapped out in advance in case of bad weather.

If you have a car (not a van or SUV) it will not be comfortable sleeping. Have you considered taking a tent and camping? That's still cheap and allows you to stretch out at night - honestly sitting in a car for hours and hours and then trying to sleep in it is not pleasant or even healthy. Look up deep vein thrombosis and reconsider that plan.

Economics lesson? You're talking $700 just for gasoline. Triple A estimates that it costs about 50c a mile to keep a car on the road so how does the economics of $2500 for this trip sound, before you even stay in a motel? And I don't really see how you're going to be in L.A. in five days unless you don't stop in DC or really anywhere else. ( L.A. is not very exciting on New Years Eve anyway, at 9pm they watch the festiviities from back east, which is probably where you should stay.) Yeah you could take the "southern route" but you can't avoid the north if you're going back to Maine, so allow time for inclement weather. Or, fly out and spend a few days then fly home....much cheaper in the long run.

Good point about the cumulative wear and tear/cost on your car. Many times on driving trips - we will rent a car for a week/two - and figure that into the cost of the vacation. Check out www.carrentals.com, among other sites.

And to make it more of a sense of adventure - if you did take some camping gear (you can usually buy some relatively inexpensively if you shop around - and a tent for two/three will work nicely - plus warm sleeping bags, blankets, layers of clothes - and an air mattress or pad - as you want to make sure you are not sleeping directly on the cold ground) - that would not only be more "economical" and far superior to crunching up in the car.

You could buy a small/portable burner - or even a small Weber type BBQ - and with a traveling cooler (ideally a hard plastic type) you could be pretty self sufficient, even if you were held up some place for a day or two due to weather.

There are plenty of campgrounds across the US - with showers, etc - some even with quite reasonable rates. So just google away to make sure which ones are open. And don't forget Government Parks, Native American Reservations, and the like. Sometimes you can find real good deals there - and you might check on getting a National Parks pass, whatever.

As for New Year's - they put on a great show in Las Vegas (4 hours driving time from LA) - and even down here in San Diego - they do it up fairly good.

In a car Xcountry with a teen boy, sleeping in the car? Stock up on some body wipes.

My style of travel includes an Amtrak 15 day USA Rail Pass for each of you. Stay in HI Hostels http://www.hihostels.com/
My plan would be to start the trip at the Boston Amtrak station.
Take the Lake Shore Limited to Chicago. Stay at the HI Hostel on Congress. From Chicago take the Southwest Chief as far as Albuquerque NM. Stay at the Route 66 Hostel on East Avenue (not HI). Take the Southwest Chief on to Los Angeles and stay at one of the three HI Hostels in the LA area. South Bay would be my choice. When you are done in LA or Las Vegas, take the Amtrak bus to Bakersfield and take the San Joaquin to Sacramento. Spend a night in the Sacramento HI Hostel which is my favorite Victorian mansion. Take the California Zephyr (leaves SAC 11AM) all the way to Chicago to take the LSL back to Boston. Sleeping in coach is slightly more comfortable than sleeping in a car. Boston also has a HI hostel if that helps you. amtrak.com

It sounds like you are flexible with lodging, since you have a car probably a good idea to pick up an inexpensive 2 man tent and some sleeping pads and sleeping bags and have them in the trunk. Pick up some of the Roomsaver magazines at the welcome centers along the hwy and use the coupons when you want a motel. Go onto the government sites for National Parks, Forests and Bureau of land management areas for inexpensive, or free places to spend the night.

Check the weather and head west then south or south then west depending on forecast and/or speed to get you to the part of the country that has wonderful National Parks to see, I'd head for New Mexico or Arizona as quickly as possible then do some site seeing in places like Grand Canyon, Death Valley, Carlsbad Canyon, Saguaro, Joshua Tree, White Sands etc. before heading to California.

Have a wonderful trip.

I love road trips and travel with my teens, but for some reason this strikes me as a punishment rather than a lesson. Camping equipment and decent sleeping bags aren't cheap. I'd save the money and spring for a couple of extra nights in motels where you would be warm during the night and well-rested for your drive. I often eat out of my cooler at rest stops, but sometimes it is nice stopping at a McDonald's etc along the way for a cheap meal or shake. What is your son interested in seeing on your trip?

Getting him a job in a sweatshop for a week to teach him about economics might be more humane.

That's a lot of hard miles on a car there and back. The cost of a rental may very well outweigh the cost of a breakdown. tomfuller's train and hostile idea seems like an interesting alternative.

Here's what I would do:

On the way to LA, take the northern route, suck it up and pay for a motel every night. You can find really cheap motels with some advance planning and it will be too cold to sleep in your car.

On the way home, camp as much as possible. BLM campgrounds are usually free (with few amenities). In some places you can camp for free on National Forest land. But again, you would need to do some advance planning to know where those spots are.

My reasoning is this: like I said in my first post, you have about 5 days of driving just to get to LA, so take the shortest route there since you only have 6 days to do it. You won't have much time for sightseeing along the way, but at least you can drive through the mountains in Colorado and see some scenery there. Then, on the way back take your time and sightsee on the southern route, camping to save money.

Keep in mind that you are only going to have about 10 hours of daylight so you'll want to maximize that time, you can drive for awhile after dark to make it to your next destination but you don't want to sleep in and waste daylight hours in winter.f

And if you insist on sleeping in your car, at least find a well-lit truck stop parking lot. That's safer than out in the middle of nowhere and they have showers, food and somewhere to go sit and read the newspaper or whatever - with 13+ hours of darkness you're going to want to find something to do other than just sit in your car all night.

Wendy, do you have an exit plan, in case you want to murder your 16-year-old in the middle of nowhere??

I do think there is a bit of edge to the teaching here. Sleeping in a car is a really dangerous thing for a woman and teen to do in the first place, let alone being unhealthy. There are cheap motels along the interstates out west.
OP, have you driven across the US to see the long distances with little relief? It is a great learning about the vastness of this country. We did it with our family and with a lot of things to entertain them.
Also, is this really to just see family in LA and driving seems the cheapest way? It probably isn't.
Camping in December isn't a really great option without a lot of appropriate equipment. It also is time consuming.
If you do the math, it will be cheaper to fly.

I hope that you are not hostile toward Hostels. I have stayed in many of them including the Route 66 Hostel http://www.tripadvisor.com/Hotel_Review-g60933-d570950-Reviews-Route_66_International_Hostel-Albuquerque_New_Mexico.html
It is on Central Avenue in Albuquerque which was the old US 66. The eastern end of the old Rt. 66 is at the intersection of Jackson Blvd. and Michigan Avenue in Chicago.
This past May, my DW and I traveled in coach on the Amtrak Empire Builder from Spokane to Chicago and on the LSL as far as Cleveland. We returned to Cleveland 11 days later in our rental car and returned to Spokane where our car was waiting for us. If you can spare the extra money for a roomette on your long distance train it would be more comfortable with the available shower.

I am taking a break from this thread until this first time poster returns with some questions and feedback.

What economics lesson are you trying to teach your son? To get across the US and back as cheaply as possible? You can fly to LA from Boston for less than what you will spend on gas.

I am betting this is a troll. It really is a bad idea, and in the winter to boot. Joke's on us.

Yup, first post for her.