Welcome to Sunline Owners Club!
There has been many on the club who have gone through floor rot.
Here is a Google Custom search on the forum on "floor rot"
radio - Google Search
That should help get you started.
Here is also a link to the FAQ forum with hot links to others water repairs. Scroll down and you will find them
Pictures are the best way to help show us what you are up against to help offer better tips.
One tip I will leave you with, when you take the floor apart, be on the hunt where the leak or leaks started? Water worked it's way on there some how, need to find the source/sources and stop them before putting a new floor in.
Good luck and hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
Google Custom Search For Sunline Owners Club