Camping in Cody, WY

Yellowstone has two loops, basically, mostly two-lane roads with some passing lanes. The speed limits are 45 over most of the Park, however, in a good part of the Park, it's hard to go that fast anyway. The lower loop goes from Grant to Canyon to Norris and back around to Old Faithful and to Grant. The upper loop goes from Canyon over to Mammoth and then back around to Norris. And don't worry about speed limits, if you are staying for a while, speed limits are illusionary, not mandatory. I would suspect average speed in the Park is less than 25 mph what with all the stopping to see sights and animal sightings, etc.