Hello everyone! I've found an easy way to open up new islands to rule in the demo while we wait for the full game. Here's how:
1. Open your Tropico 4 Demo folder and navigate to Packs --> maps.
2. Back up these files to another folder.
3. Delete or rename DoroDoro.hpk (this is the first campaign mission).
4. Rename another hpk file. Example: HoroHoro.hpk --> DoroDoro.hpk or DLC-SaltoAngel.hpk --> DoroDoro.hpk, etc.
5. Start game. Select Play --> Campaign --> Play --> Select avatar.
Here's an image of each island in-game. Some of them are exactly the same, while others have different buildings or starting locations.
This doesn't enable the building of buildings not available in the demo, except for the Ministry and any others that were available for building at one point or another (I can't remember, putting this post together made my head hurt). I only loaded most of the islands very briefly, but the ones I played on for a while didn't crash the game. Some of the new buildings are already built on some of the islands with full textures, while other buildings (new and old) are textureless.