Congrats on your purchase. Didn't know the Catalina was a class c until I went to the Coachmen site and discovered that in 2001 it was. The Catalina today is a travel trailer. The owners manual is available at the Coachmen site if you do not have it. http://www.coachmenrv.com/OwnerManuals.aspx It does not have anything about your storage under the bed. In my coachmen the storage under the bed is accessed from the outside storage doors. The rear window is normally the emergency exit, but you could add your own screening with velcro and then have the ventilation you want.