Not knowing what you time line is - is a handicap; but, Going east I would head up to Yellowstone and stay at Flag Ranch Resort so that I could see both Yellowstone and Grand Teton. Then head east stopping at Riverton, then follow the Oregon Trail back through Nebraska to Iowa. Coming back I would head up to I-90 and come west to Mt Rushmore, then north to Theodore Roosevelt NP, then west to Glacier NP. Then back down through Idaho on Hwy 50 and 60 to Reno and home. It is about 4400 miles and approx.. 8 days of driving time. There is a lot of History along these routes so my advice would be to look up the various states Tourist links and ask them to send you tourist brochures. Take your time and don't make the two biggest mistakes most people make when traveling. 1. You most likely will not drive this route and will be able to see it on your next trip through. 2. When shopping, you won't find it cheaper at the next store and you will not come back and buy it later.