Mrs G...I live near Yellowstone in Montana and have a couple of tips. If you're coming in from the Rushmore direction you could enter the park through Cooke City (NE entrance) or Paradise Valley/Livingston (North entrance). The Cook City option takes you over an incredible pass but in May it may not be open...Beartooth pass. Google Earth it, you'll be amazed. BTW May is going to be cold at night, but if you're tent camping the bears might not yet be out causing trouble. Not kidding, get some bear spray if you hike in the park. Not to alarm you as incidents are really rare but it's the safe thing to do. The Livingston route is always open and is nice too. If you go that way consider a night at Chico Hot Springs, for a nice room and a soak and a good restaurant. During high season camping is crowded and you'll want to get where you are looking to camp early in the day. Claim your spot and then go sight seeing. There are some campgrounds that can be reserved ahead of time but not all. My favorite part of the park is the northeast corner...Lamar valley, etc. More wildlife to see and fewer traffic jams. The west side of the park is more about geysers and waterfalls and stuff. Cool but more crowded. Go out the south end to see Jackson, but while the peaks and lakes are beautiful the town is really pricey and trendy. Like Aspen. As to the pass, one advantage is that there is a quick lane at the entry gates for passholders, so you avoid wating in line. Sounds like a great roadtrip.
