Basically anything that is considered "stationary" can be put in to the base map, but stuff that might get tossed around, moved, etc. should probably be added later as a stamp. Generally doors and windows are fine. Some GMs like to have the door as a separate stamp so that they can actually "open" it for the PCs but I think they are in the minority.

There is another thread that lists various things to not include in a VTT map. If you click the New Posts link at the top you should see it in your list.