I figured it out! It looks ugly.. but the terrain is there!
It's actually pretty easy, I just never played around with sketchup before so I never realized it. Here's how:
1) Geo Location --> Add Location, and then find the area you want to have the terrain of
2) Click Select Region --> Grab (more specific area selection), and you should have a 2D terrain map
3) File ---> Geo Location ---> Show Terrain, it will now be 3D
4) Export as a .3ds and load into Nolimits 2!