Take a look at the frame...
If there was enough water there long enough to cause the aluminum to corrode, I'd be concerned about the frame underneath as well.
It might be worth pulling the belly pan right there just to assure yourself that you still have good steel supporting the floor.
AIR 2053 Current: 2006 Born Free 32 RQ Kodiak Chassis, & 1995 Coachmen B-van
Former Airstreams: 1953 Flying Cloud, 1957 Overlander, 1961 Bambi, 1970 Safari Special, 1978 Argosy Minuet, 1985 325 Moho, 1994 Limited 34' Two-door, 1994 B190 "B-Van"