Log on to McMaster-Carr
and look for catalog page 3482. Item B makes good trim if you can fit the floor within 1/4"; that was easy with my cork floor in the International. The glossy black molding looks great with any decor. There are several other shapes that may be useful for trimming other places in an Airstream.
There are a lot of other moldings that can be found by searching McMaster-Carr for "molding" or "trim". I find them very easy to order from and shipment is always quick.
Outwater Plastics also has a lot of moldings, but McMaster-Carr will provide it in more reasonable lengths for our use.