Niagra falls-Washington DC and area roadtrip with teens
 

I’m planning a trip with my teenage children to the US this summer (late June-early July) and am thinking of taking a 5-7 day road trip out of Newark in addition to a few days in Manhattan, where they have already been.

Looking at the map, it looks like we could go up to Boston via Newport, then to the Finger lakes for some nice nature scenery and from there to Niagra falls. Then drive down to Washington DC maybe stopping at Hersheypark and finally up to Philadelphia and back to Newark.

What do you think?
Is this doable in a week?
Do I need both Boston and Philadelphia or drop one? and if so, which?
Any tips about where we should stop to eat and sleep?

Both Boston and Philadelphia have a ton of history. I would choose one and plan another trip to the other for another year. Check the prices to fly into BWI and renting a car there vs. Newark. BWI is a lot closer to Hershey than Newark. Both EWR and BWI have Amtrak stations attached to them.
For your route from Niagara Falls to Hershey, I suggest going via Corning and seeing the Corning Museum of Glass. Don't even think of US 219 and 153 to get to I-80 near Clearfield PA.
In Rochester NY, the children might be interested in the Strong museum of toys or maybe the George Eastman house. It is sad to see what happened to Kodak

Let's see: Newark to Newport to Boston to the Finger Lakes to Niagara Falls to Hersheypark to Washington to Philadelphia -- all of this in five to seven days, WITH teenagers.

It's a wonderful drive -- you just won't have enough time to actually SEE anything.
And I'm the kind of traveler who thinks nothing of traveling 700 miles in one, 14-hour day of solo driving.

Tom Fuller is right: spend a week in Newport / Boston / New England OR Philadelphia / Washington. Either choice would be great -- just pick one and be happy.
But don't even THINK about doing both -- it can't be done.

Drop Washington DC and do Newark, Boston, finger lakes, Niagara, Hershey, Philadelphia, and back to Newark.... this circle allows you reasonable drives and overnight stays with some

time to look around...

This reminds of the time we visited DC and DH really wanted to go to Mammoth Caves in KY. The bonus was a tour of the Corvette factory for our young teen's birthday. What would your teens do? If you do Newport, they might like Beneath the Breakers tour. You could also swing by the Native American Museum at Foxwoods in CT. For splendid scenery there is NH's Lakes Region/White Mountains with hiking, zip lines, mountain biking, etc. Highly recommend a nature cruise on Squam Lake to see loons and eagles. Maybe Canobie Lake Park for amusement park which is only about 30 minutes north of Boston. Throw in Portsmouth NH if you want more history focus.

It sounds like a case of self-imposed torture, as it about an 800 mile round trip from New York/Newark to Niagara Falls. The Falls unless you follow the complete guide by the local Chamber of Commerce, is 1/2 of sightseeing.

Don't you want to spend at least a whole day in Boston seeing historic things, and another in Philadelphia, a day swimming, tubing or rafting on the lakes, etc., etc.? D.C. Needs a minimum of two or three days to see much of the many wonderful things there. Hershey Park needs a day. You really have more than enough for two trips. Seems to me you should figure out some of the things you actually want to see or do, then make your route. Since they have seen Manhattan, perhaps skip that this time. Aim to be in one of the big cities for July 4th.
Consider touring Nemours Mansion in Delaware.
Where are you coming from?

Thanks for all of the comments and good information.
I guess I need to think about it some more

We've done a lot of East Coast road trips, being based in Mass. Here's what I'd recommend. Focus on Philly/Hershey Park planning first and determine how many days you want for those locations. The amusement park is a full day, the chocolate tour stuff is pretty interesting for half day. Philly - the Duck boat tour gives a nice overview of the city and between that and Independence Hall area you have a full day of History - there's a ton to do in this city so identify what else your family would enjoy and see how many more days you need there. Add in one day for Gettysburg IF that is interesting to your kids (hire a guide who drives your car around the battlefield - this is so worth it!). Depending on number of days left for outdoor time consider Poconos or Shenandoah Valley area. Finger lakes are pretty but I think you'll get more options in Shenandoah area.

Or - focus on Shenandoah area for a few days and Washington DC for a few days - that's a really nice mix of history/city/outdoor time.

If you did D.C., you could go a couple of hours drive South and also do Williamsburg and Busch Gardens and Water Country. On the way, you could tour Fredericksburg, which is historic and charming. Busch Gardens is a wonderful amusement park, clean, pretty, great rides. Just A half hour South of D.C. Is Mount Vernon, Washington's home.

Thank
 

Thanks I will research your suggestions

Sounds like a fun trip but you need at least 10 days and preferably 2 weeks if you don't want to spend most of your time just siting in a car versus seeing and doing things.