Overland travel has been... changed. Area's are seperated into Regions, which are seperated into Zones, which are comprised of individual areas.
To give you an example, in Balifor (Region), exists Balifor West, Balifor Southeast, & Balifor Northeast (Zones), each comprising of any number of overland maps. Travel between Regions & Zones are handled by "fast travel", i.e: Boats, Caravans. These are used to simulate/traverse huge expanses of what would otherwise be empty areas. Though, they do include encounters of their own. (Caravan Attack, Encounter, etc. Sea battles, sunken ships, etc.)
Travel between area's is "seamless". What this means is, instead of there usually being one transition that leads to another transition on the next map, the entire edge of the map is a transition. Like, you can use the transition on one map, and it will lead you to that position on the next map. (Within 5 meters in-game.) This also allows for diagonal transitions as well. So, if you were on a map, and traveling east, no matter where you were when you were at the eastern edge, you will show up at the same point at the western edge of the next map, relatively in the same space north or south of where you left.
This makes terrain contiguous. It makes it so sometimes the only way to access parts of one area map is through a certain location via another map. I'll post a screenie giving an example of what I mean shortly.