Another recommendation for the Fastrack truss bridge. Have one on my layout bridging the entrance to the interior and it's fantastic. Obviously integrates well with Fastrack. Probably the only concern would be that it's only ~30" long, which may not be enough for a doorway, especially if you think you may need to eventually get appliances through.
You can configure two of them together but a pier in the middle is required. Maybe you could trim down the plastic base of that middle pier (or replace it with your own custom connector piece), lock both bridges to the central pier/connector, add some strength to the bottom of the whole thing so it doesn't sag, and treat it as one big lift out bridge? Might be too long at that point, though 
