I-80

I-80 in Wyoming is fine, they actually maintain it pretty well (we're heading west on it on Wednesday, then back east on Monday!). Your biggest nemesis there is the wind but you'll be fine in your Class C, we did it last summer with no problem with our big 5er. Also since there's quite a bit of miles between truck stops between Rawlins and Laramie, be sure you keep an eye on your gas. We usually top off in both locations just to be safe. There is also one steepish grade between Cheyenne and Laramie, but again you'll be fine, I've only ever seen older vehicles/RVs with issues there. Like Thom said, you'll probably get a nice tailwind since you're headed east.

I also haven't done the Nebraska portion in about 8 years, and that was in a car, but I don't recall it being bad conditions or anything...just very very boring.