RV Repair: Rotten floor under wall, dry wall screws, particle board

Question
I have a 2000 Prowler and the bathroom started to leak. I fixed the leak but the water had leaked under the linoleum. I fulled up the linoleum and realized it had been leaking for a while. Most of the wood around the toilet and under the back wall is rotten, also the wood under the wall that hold the door is rotten. PLEASE HELP ME. Where do I begin?

Answer
HI THERE DAVE
I'VE DONE A LOT OF THOSE BECAUSE OF THE CHIP BOARD/PARTICLE BOARD THEY USE IN THE FLOOR.
WELL, YOU'LL NEED TO TAKE EVERYTHING YOU CAN OUT OF THAT ROOM INCLUDING THE TOILET FLOOR FLANGE AND THEN THE INSULATION. THEN FIGURE OUT A WAY TO RE-FRAME SO THE NEW FLOOR WILL BE BOTH STRONG AND FLAT.
WE CUT THE FLOOR BACK AS FAR AS WE CAN REMOVING THE ROT AND TRYING TO KEEP ANYTHING GOOD SO WE CAN ATTACH UNDER FLOOR STRINGERS THROUGH THE TOP. AS FAR AS THE WALL AND THE DOOR AREA AREA IS CONCERNED YOU MAY NEED TO CUT THAT OUT AS WELL EVEN INTO THE HALL. YOU CAN'T GET TOO FAR UNDER THE WALL AND THAT MAY CAUSE YOU TO CUT MORE THAN YOU LIKE.
WE WILL THEN PLACE 2X2 STRINGERS UNDER THE FLOOR AND SECURE THEM THROUGH THE TOP WITH DRY WALL SCREWS. THEN WE CAN SET OUR NEW FLOOR PIECES ON TOP OF THE STRINGERS. THEN SEAL IT WITH A LATEX CAULK PUT OUR FLANGE  AND TOILET BACK ON AND LAY DOWN CARPET TO HIDE THE SCARES.

THOM