I just remembered this thread. This evening I am going to be playing Dominion with 3-4 people and at least one will be new to the game, so I am not going to be bringing all of my cards. I am a little less set constrained than OP, so here's the Introduction Travel Set I am going to bring. It's based on the Base Set, but replacing some cards to promote engines and speed up play a little.
From Base: Cellar, Chapel, Village, Workshop, Throne Room, Remodel, Militia, Gardens, Market, Witch, Mine, Festival, Library, Laboratory, Council Room.
In addition: Courtyard, Lighthouse, Wishing Well, Steward, Noble Brigand, Trader, Mining Village, Bridge, Envoy, Hoard.
The thinking: Lighthouse instead of Moat (decreases number of terminals, still gives defense), Wishing Well instead of Spy (more fun, moves more quickly in multi-player, more useful), Noble Brigand instead of Thief, Hoard instead of Adventurer (introduces alt money, more useful, fun to gain golds!), Trader instead of Bureaucrat (gains Silvers, moves more quickly in multiplayer, is a reaction since I removed Moat), Mining Village instead of Feast (another Village and non-terminal to increase engine opportunities; still has one-shot quality), Bridge instead of Woodcutter (useful more often), Steward instead of Chancellor (still gives money, but draw and trash increases engine options).
The big change: I removed Smithy and Moneylender and replaced with Courtyard and Envoy. I had removed some drawing and added trashing in the above changes, so there is room for some more draw, and Envoy and Courtyard are both fun twists on Smithy. By removing Smithy and Moneylender, there is room for both!