First, look at the opening dates of facilities inside Yellowstone. Make sure you click on the link under Road Information for Opening/Closing dates (scroll down to find the projected opening dates for next spring).

You kind of need to have that info in hand to make decisions, especially if you're looking for lodging inside Yellowstone.

And it's a good link for everyone else to look at so they aren't recommending you go somewhere that isn't open at that time of year.

http://www.nps.gov/yell/planyourvisit/open_closedates.htm

Good chance a lot of the roads and facilities will be closed. Sometime the roads don't fully open until after mid-June. That was the case when we were there June 16-20, 2010. Opened the day we arrived.

We went over Memorial Day weekend and the first week of June and roads were closed. A lot of the trails were closed also. That said I would stay in the parks. The amount of time in each park depends on your interests. I would read some trip reports to get a feel for your answers. Myer and others have great reports.

It's way too far from Jackson or Bozeman to do Yellowstone. West Yellowstone would be fine but it's preferable to stay IN the park. It's a large park and driving is slow and long.

Take winter clothes and rain gear for that time of year.

Starting to re-think this as roads may be closed. Thanks for all your input.

As ziggypop wrote, I wrote a very detailed trip report but I was there the first week of August.

I imagine it's a very different park in mid-May.

you should be able to see a lot of it, but to get from one side of the park to the other could be difficult. I would imagine that area around OF would be open. I think the section from Canyon to Tower is generally the last section to open.

The section from Grant Village to OF may be closed--it crosses the Continental Divide 2x.

I believe Grant Village is not open at that time.

My only concern is that I see particular roads that are SUPPOSED to be open at that time, but there's a caveat - depending on what the road conditions will be like. No one can tell what that will be.

I thought to stay in Jackson the last 3 days to see the Grand Tetons, and to easily get back to the Jackson Airport, not as a place for Yellowstone. The Old Faithful Snow Lodge is open at that time and thought to stay there. I think staying near the North Entrance, or even in West Yellowstone, would be too far for us to travel in the time we have.

It probably would be better to go at a different time. However, if this is the only opportunity for you to see it, then don't miss it. I love National Parks and have been to a lot of the US NPs. It is really a complete park. A little bit of everything. Wildlife, geysers, natural beauty, etc. Something everyone should experience.

When I went last year in mid-June it was a snow nightmare a week earlier. No one had thought the winter had been that bad and some roads only opened June 7 including Sylvan and Dunraven Pass. Lake hotel and lodge were open but some trails had 3 feet of snow on them. I was joking that I should rent snowshoes for the week. If you are aware of closures and plan around them then by all means go but if you dont want the hassle of all the extra planning and extra driving then try to go at a different time.