We are visiting colleges in the Denver area. We will be flying into DIA and staying for three nights. After that, I do not know what to do. I have read that car rentals are more expensive at the airport. I am looking for suggestions on getting around and where to stay. We have tours in Boulder, Golden, and Denver. Should we stay in Denver or stay one night in each location?

I would be inclined to spend a night in Boulder for sure, just to get a better feel for the city than you'd get on a tour. Not sure about Golden.

I've rented cars from downtown Denver and the airport, some times downtown is significantly cheaper and some times it isn't. You'll have to price it out for your dates and see what the cost is. It is relatively easy to get from the airport to a couple of the downtown car rental locations, but no point in doing that if the savings are not significant.

Is renting a car a necessity? Where would I rent one if not the airport? How would I get to the rental location? Are there shuttles to Boulder? The main issue is my limited budget. This is a spur of the moment trip.

Yes, a car is a necessity. In what order are your tours? I'd try to do the tour in Golden and then head to Boulder for the night and a tour the next day. What school are you visiting in Denver?

Boulder is 1st and then school of mines and C.U. Denver.

It may be more expensive to rent at the airport but is it worth the falderol to get a taxi/shuttle or whatever to somewhere in Denver to rent, etc. Sometimes, and for a short visit, just pay the tariff and figure out the ins and outs for another time.
I'd stay in ONE place the whole time. Choose. why move around.

I wouldn't stay in one place. I'd do something like this:

Day 1: Rent car at DIA and drive to Boulder. Spend the night.

Day 2: Tour CU, drive to Golden, take CSM tour, spend the night in Denver.

Day 3: Tour UCD fly home or spend night in Denver.

Why move around? Because they are visiting colleges and will get a better feel for each particular campus by staying in the immediate area for a night, rather than driving in for a tour and leaving immediately.

To the OP: You can can look at the Denver public transit system to see if it fits your needs for this trip. There are shuttles/buses called SkyRide that go to Boulder from the airport. Light rail would get you from downtown Denver to School of Mines and C.U.

The only tricky part is getting from Boulder to Golden. It appears you would have to take a SkyRide shuttle from Boulder to the Airport Blvd/40th Street stop, then disembark and catch a different SkyRide shuttle back to downtown Denver, then take light rail to Golden.

http://www.rtd-denver.com/SkyRide_Map.shtml
http://www.rtd-denver.com/lightrail.shtml

That trek from Boulder to Golden would be a hassle and the fares may add up to more than a rental car, especially if it's two parents plus your child.

As for your other questions: I've rented from Budget in downtown on Broadway, I believe there is a Hertz and/or Enterprise nearby. I've taken the SkyRide shuttle to downtown then walked 5 or so block to Budget. SkyRide is far cheaper than a cab for an individual, but you'd need to price everything out based on the number of people you have going on this trip. If there are 3 of you, a car from the airport is the simplest option and not cost much more than using the SkyRide and light rail systems.

If you drop the rental off when you get to Denver and then take SkyRide back to the airport you may be able to save on the car rental cost and hotel parking.

I'd also recommend visiting CSU in Fort Collins over CU Denver.

The problem is we are arriving at night. It seems a waste to rent a car just to get to the hotel. The tour in Boulder is at 9am the next day.

Boulder is 40+ miles from the airport, hardly a waste to rent a car that you will need to get to Golden the next day. You are making this way too difficult. Have you even priced a rental car yet or looked at a map?

Some of the advice concerning public transit in Denver/Boulder is a little off. Go to RTD.com for all the schedules. I think you can do it all on public transit. The SkyRide buses are designed to take you from specific points in the metro area directly to the airport. They may pick up at a couple of different points but mostly an airport run. There are buses directly between Boulder and downtown Denver.

Since you are arriving at night I would take the Skyride bus from DIA to Boulder and spend the first night in Boulder so you can do the 9am. From Boulder that day take an RTD bus back to Denver that PM and stay somwhere in downtown Denver for the next two nights. From downtown Denver you can walk to CU Denver. For School of Mines, you can take the light rail from Denver to Golden and cab/Uber to Mines. And then finally you can take the Skyride from Denver back to the airport.

Yes, I have looked at a map. Money is the problem. Rental rates are around $100 per day unless we use Fox. I have read bad reviews of that company.

Man23 - we use Fox evey time we go to Denver. Haven't ever had an issue.

fmpden gave you the best route if you want to use public transportation. The Skyride bus is like a big Greyhound style bus, very comfotable.

Some of the information from above is coming for those who do not live here. Denver has decent public transit systems. Not as good as NY or Chicago or many European systems but better than most cities of Denver size and larger. Using public transit anywhere requires some patience. You are trading time and some inconveniences for money.

I did some quick checking of schedules. The last Skyride bus to Boulder goes at 12.41 AM and leaves each hour around -41 and takes an hour to the Boulder transit center. You might get off one or two stops earlier depending on location of your hotel. You may have to take a short taxi/Uber ride.

The regular bus from Boulder to Denver's Union station runs every 30 minutes. So you could easily catch it back to downtown Denver when finished in Boulder. Boulder is a very small campus so it is easily walked from one end to the other. At end of day, circle back to your hotel, grab luggage, and take bus back to Denver. About an hour ride.

The next day you can take the light rail to Golden. I have not ridden that line so am not sure how close it comes to School of Mines. At the most a short taxi ride. The run to Golden is three or four times an hour depending on time of day and about an hour.

The CU Denver campus is right downtown so you can walk there any time.

PS What is the dates for your trip?

There is a bus that runs between Boulder and Golden, with stops close to CSM and likely more convenient time wise than Boulder to Denver to Golden.

www3.rtd-denver.com/schedules/getSchedule.action?routeId=GS

Wtmoo3 has the best suggestion.
Try airport rental pricing a few more times; I was surprised at the terrific price I got visitors (even around memorial day)this year.
Try carentals.com or other sites before you go the mass transit route. I have a kid in Denver (DU), and the bus to light rail to bus just to pick her up at the Boulder stop takes hours. (When we pick her up by car for a visit it takes 45 minutes each way, door to door.)

I suggest you get a car, so you can see more of Boulder, Golden and Denver. Costco.com/travel has good deals. Keep checking Kayak, too.

And I agree about CSU @ Fort Collins. It has gotten very popular with CO kids who are choosing it over Boulder.

I imagine you know about University of Denver, and Regis, as well.

Enjoy your trip!

T2 - You need to reread the postings. There was no reference to CSU so not sure who or what you are agreeing with. Three schools in the mix were Boulder, CU-Denver campus, and School of Mines.