Skull Rock
Tiki Tiki Tiki Room
Jungle Cruise Explorer's Tent
Nautilus Submarine Room
Though I'd be perfectly fine with Briar Patch and Mark Twain Steamboat replacing Tent and Submarine
Dark Ride Room is very useful, but I feel it fits better as a buyable room for a fairly low price. The starter rooms should have some "personality", and the Dark Room doesn't really have any because it's purpose is to be a blank slate where you can build rides and games. It's very useful, but the room itself is pretty boring.