Hi,
I did Rockies and Alaska in 2008, my first JY trip. It was a wonderful experience, wonderful scenery, good hotels etc. It's a very busy trip but very enjoyable.
I haven't done Parks and Canyons but have heard from others that it is another wonderful trip.
I'd be interested to hear about the rail journey as it's one of the trips I quite fancy.
I'm sure whatever trip you opt for will be enjoyable. I've since been on South African Explorer with Zambian add on, this year I did Austrian Lakes. All very different holidays but all very memorable.
Janice