Road Trip to Yellowstone - Help!

The key to your post is that you will be visiting in Mid-September. The park will still be busy but not like July and August. We just wrapped up a 9 day visit to Yellowstone and the surrounding area (mid-Sept 2015). Nice weather and low gas prices = unusual numbers of visitors for the post Labor Day Period. We did one tour with our toad and were gone for most of the day with the 2 dogs. It was exhausting traveling in the car without the use of our bathroom, kitchen, and RV to rest in. We did a 2nd day tour with the RV and had no trouble finding places to park. (Our RV is 27' Class C). (We had the toad behind us). We are learning that we don't like car trips! I vote for taking the RV!! Old Faithful has a HUGE parking lot and plenty of places for RV parking. If you bring bikes, you could add another dimension to the trip by biking on the smaller park roads that DO NOT allow RVs or buses.(I would not recommend biking on any park roads that have RVs or buses on them). It was busy almost everywhere we went but there were always place to park the car or RV. If you have time, the drive between the East Gate and Cody WY is not to be missed. Tons of camping options on that route and also inside the town of Cody itself. Try to spend 1 night at Newton Creek Forest CG 20 miles outside of East Gate $15 great place of indescribable beauty. Wapiti Forest Service CG (between East Gate and Cody) also very nice and has electricity at most sites. Check on closure dates as these do close for the season all at different dates.