I really like the trails idea!
Since they are supposed to be forgotten places and hard to get to, cards like those really work (for me, at least). I'm also a fan of Strangers who drag you to different regions entirely. A Wood Nymph takes you deep into the Woodlands, a Goblin grabs you and drags you down into the Dungeon, etc.
If I remember correctly, there was a homebrew that had only four or five cards. Each was for the main Adventure deck, and each was a Stranger (or Event?) that carried you away to a different board.
I also like this path idea. Being moved out of the region now and again certainly makes a small region seems larger.
Two things I don't want to see from you thoughts is random purchase cards (since they are kept sorted) and moving to other regions than woodland, Highland or the main board. I don't think all expansions should be needed to play with the lost realms.