Hi,
We had an amazing time doing that trip this summer (except coming from SW MO). There's so much to see. I've been blogging about our trip. You can find links to my posts with lots of photos, campground reviews, and suggestions here:
Road Trip. I haven't covered Yellowstone yet, but I will be doing it soon.
We did enter Yellowstone at the east entrance. If you are going into Cody, WY, the part of the trip that you need to pay attention to is through the Big Horns. There are 3 routes--one isn't recommended for RVs, one is adventurous but doable, and one is relatively easy (that's the one we took--Highway 16). The part from Cody into Yellowstone is no problem at all.
Have fun trip planning!
