Welcome Back From the Florida Panhandle
Welcome to the Forums. We're glad to have you with us.
We also have an '05 25, but ours is a front bedroom/queen. We have spent over 320 nights in ours, and the mattress is still good. I like it better than the one at home. We use a memory foam 2" mattress pad that we got from Camping World. Check the mattress out before you replace it; it well may be savable. If you do need to replace it, check with Airstream first because of the unique shape. Then go to a foam supplier, pick out the appropriate firmness. Get a quote from them cutting it to shape, using your old mattress as a pattern. Compare the prices and decide. You may find that you will get better quality for you money with the foam supplier.
As for the cleaning, it's the same as a house except a lot faster and easier.
As for keeping dirt out, we do really well with an artificial turf type mat on the ground next to the steps. Get the one from Camping World which is intended for use on RV steps. It has holes all over the bottom for water to drain through. It's the only one we have found that really works well. Then we use another foot wiping mat right inside the door.
Good luck in your new Airstreaming lifestyle. Let us know how you are doing.
SuEllyn & Brian McCabe
WBCCI #3628 -- AIR #14872 -- TAC #FL-7
2015 FC 25' FB (Lucy) with HAHA
2005 Suburban 2500 Quadrasteer (Olivia) & 2011 Silverado 3500 (Fred) with Outfitter Truck Camper (Ethel)