No clue if this would be up your alley, but the best spring break trip I took with my family was to a dude ranch in the Texas hill country (cue steers/queers jokes). I was 12 or 13 at the time, my brother was 9 or 10. Horseback trail riding every day, sleeping in a log cabin, meals around a pit fire when they rang the triangle (including 6 am steak for breakfast every day), campfires every night... great memories, and completely different from the standard Disney World fair.
Genius.