One of my favorite trips (perhaps for slightly more adventurous family):
- Fly to Juneau
- Take the Marine Ferry to Haines
- Bicycle up over the coastal range to Haines Junction, Whitehorse and back to Skagway
- Take the Marine Ferry back to Juneau
Beautiful wilderness, not much traffic, ferry/wildlife and dramatic scenery, particularly over coastal range and back.
On the other side of the equation. There are a collection of youth hostels on Cape Cod (Truro, Eastham, Hyannis, Martha's Vineyard, Nantucket) that are all ~25-50 miles apart along with nice ferry rides to the Islands and also some stretches of rail trail. These can get strung together in distances not too far apart for an interesting summer trip. [It has been years since I've been there, so perhaps has changed, but I encountered a number of youth groups that did organized trips to Cape Cod for cycling/hosteling].