I agree with glas. We got a mirror cracked several years ago (when in for maintenance) and replaced it with a beveled edge from Lowes or HD, using the original border molding. Still looks great after these several years. It is in the same location as you describe, on the wall that is hidden by the slide next to the dinette.
Ken, Judy, and the Angels--2005 Fleetwood Southwind--2008 Cargo Trailer--2003 EZGO Golf Cart