New vehicles include: A new type of tractor, a full-winged dodo, and a motorhome. The twelve 'small' towns are also marked, and Mount Chiliad is placed between Los Santos/San Fierro (As expected)
The map is certainly not official, although it does indicate the positions of each city - and where to expect particular landmarks. German magazine 'Screenfun' has released four new screenshots and a sketched map, in a recent San Andreas preview. I'll start with some of the hidden interiors, which we all really know about here, so I won't talk about how you get to 'em or anything. Its amazing what you can find in the game's code.
I just figured I'd post all the stuff originally learned on GTAWH to here.