I've been browsing 2D maps on free-to-download star wars map sites, and found a great, huge, Hoth map. I enlarged it slightly so it's a bit bigger than 1" grid, but the right size for Action Fleet starship models, and also big enough that when I add 3D walls to the base, figures can fit in the rooms and passageways.
So far, all I've done is print out and tape together the floor map. First though, I used PhotoPaint to edit out the drawings of space ships, so I can put whatever I want in the hanger. I also used PhotoPaint to remove the turrets from around the trenches, so I can sit Star Wars Miniatures turrets wherever I want, when using them in a battle.
Next I'll be adding 3D walls to the map, and a massive opened hanger doorway at the front of the hanger. Then I'll be adding 3D computer consoles and that sort of thing.
So, here's what it looks like with some scenery objects and a handful of figures thrown on as well. I like how it's looking so far, and the original artist who designed the map did a fantastic job (CPreska's map, downloaded from The Holocron: Star Wars Miniatures).