We went to Bryce, Zion and the Grand Canyon last July. We spent one night each at Bryce and Zion and then two nights at the Grand Canyon. That's all the time we had since we only had a week and had to drive from Austin, TX. We stayed in the Nat'l parks in the lodges there. I would highly recommend doing that at Zion and the GC. Just getting into these places from the "outside" seemed like a trek. There were a couple other hotels/lodges outside of Bryce that are fairly close, but if I were to go again, I would still stay on site. It's great to just get up in the morning and walk to the rim! We did some hiking (at least two short to medium hikes in each location). Here's where to find info. about the reservations at the lodges:
http://www.grandcanyonlodges.com/ http://www.xanterra.com/ We stayed at the Thunderbird Lodge (GC), Zion Lodge (not one of the small cabins, but the larger building??), Bryce Lodge (also a larger building, not the small cabins). We loved the Bryce and Zion Lodge (especially). Our view at the Thunderbird in GC was ok. We could see the roof of our old "dorm-like" building below our window between us and the rim.
Definitely get the National Parks pass if you're doing more than one park.
My girls were 10 and 8 at the time. We took a little time at the GC to do the Junior Ranger booklet and get their certificate. We didn't have time to do that at the other two parks. Visit the visitor's centers to ask about this. Also, visit the National Parks service website for more info. You should be able to find maps of all of the trails. I know we did the Bright Angel trail to the first stop at GC. Our second hike there was to a Ooh-Ah point. Both of these were doable hikes (with preparation and proper food/water/clothing). It was pretty hot in July down there, so I imagine in April, it would be better below the rim. Zion was my favorite of the three parks. We did the "river walk" trail?? and the weeping wall - both pretty easy trails. We also did a trail to the emerald pool (lower??) right across from our lodge. At Bryce, we drove around to the some of farthest points one afternoon, walked the rim near the sunset point (near the lodge), then in the morning we went below the rim for a short distance (most of the trail we wanted to do was closed because of a rock fall). We did one more short hike to the "cave/waterfall??" (one that started outside the park) before our drive to Zion.
I can't help with the other questions either. Sorry.
