Ron,
I have replaced the bottom flooring such as you are describing. The biggest challenge is removing all the obstacles in the way. You will have to replace it in sections to get in in thru openings. Purchase the fabric vinyl from your local RV dealer or online and secure with 3M-08090 contact cement. Use urethane windshield sealer on all exposed joints when you assemble and install the floor. Secure with self-tapping screws and trim off excess. Fun project if you approach it with an attitude of gratitude! Blessings, Fred