Welcome aboard, Roadster. Sounds like you have bitten off quite a chunk right off the bat. Anyway, first, search the forums for repair work as you need, and most of the time, you will find pictures that will show step at a time work previously done by someone else. Be advised, the floor is tongue/grove for good support, and depending on your year, may actually be pressed wood flooring. No matter the case, you have quite a job in front of you. Hope you still love the thought of an Airstream two months from now.
2000 390 Landyacht XL
1989 29' Excella
WBCCI #6673 jerry Hodge
Have no intention of arriving at the grave safely, but rather to skid in sideways, chocolate in one hand,throttle in the other, totally worn out and screaming
"WOO HOO, WHAT A RIDE!"