Yes, everything is paid for, except for extra food (ice cream, treats, etc) and souvenirs, and the food on travel days. I think they've rented at least 7 Suburbans, and a trailer for their gear. All this for less than $900 per boy, as they got not only the stipend that all the scouts got, but also a scholarship.
Also includes sea kayaking, camping/hiking in 3 different national/state parks, mountain biking, and the big surprise: white water rafting... they usually go in Maine every year, but going in Alaska as well? Very cool, but I MISS THEM! (But not the bickering) I've attached a photo that was taken of them and posted on their blog at the Anchorage Airport, I think my boys are right in the middle of the photo (the younger one has the watch on his right arm, the older one is next to him on the right - I think!)
You're right, they are incredibly lucky that they're on this trip... we got a sprinkler in the front yard, and snuck down to the reservoir to go fishing!