I converted the standard twin berth layout on my 345LE to a queen double bed.
Allowing for a FO (as in future owner), I have made no mods just removed the center draw cabinet (now stored) and hung an IKEA queen slat and mattress between the existing bunks. Added custom carpet along each site for adventurous exits.
Any work on water circulation will require removing the bed but...!
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.