As far as rooms go, a program utility called SignsIV will create rooms very easily. All you need are the textures for the interior, exterior and the ceiling. You can take a look at the texture files that come with the program to get an idea of how to make a texture image. Signs also creates a lot of other different stuff -- except customized entities and animated characters.
The past has a lot of memories to hold onto; but, today is chock full of new adventures, and, the future shouts out, "The best is yet to come!" -- TerryC