2011 we made that trip from Ann Arbor MI. For us we planned 7 days in yellow stone and 3 days in mt Rushmore. Entering from Cody and staying at west thumb. We have a 2000 watt gen used about every other day for a couple of hours with no problems. With all the stops and hikes it took us about 5-7 days to drive out the park. As you get near a gate go out and top off on fuel as that will save about 20-30 cents per gal. We loved YNP so much that we skipped Rushmore and stayed a extra 3 days and checked out the Tetons. Recommend a medium size ice chest to pack a lunch every day as the park is BIG.
