Yes, the water flowed to the back of the "shower room" and it is not sealed there.. the caulking is gone and moldy in the corner.. and then the water flowed down and out the bottom of the trailer under the bathroom.
Hi Lauradawn! Welcome to FGRV! Your Burro's floor may or may not be rotted under the shower. As it's a '98, the condition of the wood in the floor may not be as bad as you may suspect. The Burro
floor is plywood encased in fiberglass top and bottom. The models with the shower have the shower pan laid on top of the floor, and the drain line run through the floor. The toilet drain also runs through the shower pan and floor. The walls are installed after the shower pan is laid down, and then the whole thing is caulked where needed. There are basically only three places then, that can leak: the through-hole for the shower pan drain, the through-hole for the toilet, and the cracks that should be caulked and that may now leak.
Any or all of them may be leaking and contribute to your problem. None of them may have been serious enough or run water long enough to actually have allowed dry rot to occur. Then again, you just don't know. Mold and mildew isn't necessarily indicative of dry rot either.
My first course of action would be to take out all of the existing caulking in the shower and allow the entire shower enclosure to dry out through the cracks for a few days. Then re-caulk them, let the caulk set up, and test the shower. If that's all it was (and that's probable) then you've fixed your problem. If it wasn't, then the next most likely is that something is leaking around the pan drain. Last is probably the toilet drain. While it's possible to tear the entire shower out, and is really not even all that difficult, it may just not be necessary yet.