Sonya, I'm about a three-hour drive from YNP. Couple years back, I did a four-day trip with my GEO 275 class, Geology of Yellowstone National Park. We'd started with a six-week lecture series on the geography, history, botany/zoology, etc.; then finished with the trip.
We each had to prepare a 10-page paper. I did thermophilic bacteria, which was about as interesting as watching a croquet match featuring blindfolded players!
One of the things I did learn was that the chances of a caldera collapse ("super eruption") incident over the next 200-300 years is extremely remote. This is a good thing, because if there were an incident as big as the Island Park caldera eruption, a large portion of Idaho and Wyoming would go away.
YNP is a beautiful place indeed, but hideously crowded year-round. We usually hike the five NPs in Utah: Zion, Brice, Canyonlands, Arches, and Capitol Reef. Just as beautiful and almost as close (except for Zion, which is closer to Nevada), not nearly as crowded, and just as close to us as YNP.
Glacier NP is (or was) a great place, and it's right next door to Waterton Lakes National Park in Alberta. but a large portion of the glaciers have disappeared, and the rest are shrinking fast. I'd suggest you go quickly.
. We zig-zaged across the country seeing all the sights we could, camped most nights. Finally split up in Minnesota, i continued to alabama then virginia with a few more stops.
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