We did almost everything on this trip and then some on our own before
ABD was around. It would have been nice to have someone else handle the logistics! If your son is an active young man he should have no trouble. While ABD doesn't address it, and I don't know where you are coming from, if your son likes trains, arrival at the hotel by Amtrak is nothing short of spectacular. The station is walking distance from the Glacier Park Lodge, although they have a free shuttle to pick you and your gear up. You may be there well before the ABD folks, and that's a chance to explore the hotel and grounds and have some extra fun. The hotel was built by the railroad, and it's cool to re-live that part of history. The Amtrak trip on the empire builder either direction is constantly jaw dropping. The sleepers are pretty awesome too. Obviously, this doesn't work for the return trip, which is by air. The glaciers are receding pretty fast, and several we saw that were ginormous are gone. It might be more of an adventure than you realize to go see these while they last. If you go, and I hope you do, please write a trip report! Of all the trips my wife and I have made, with or without kids, with or without organized tours, this remains both of our very favorite places. Enjoy!