16 and 14 over the Bighorns are both tough, but doable with your rig. Avoid 14A...it is not called the Oh MY God hill for nothing. LOL
16 has several campgrounds along the way and a dump station up near the top of the Pass.
There is a nice little rv park on the west end of Ten Sleep.
Out of Cody, there are several rv parks and federal campgrounds. Two of the fed Camps have electricity. Wapiti and Rex Hale.
I advise against entrance to Yellowstone via northeast gate. The approaches are stunningly beautiful, but you won't see much of it because you'll be looking at the road if you're pulling your rig.