Howdy!
Proud new owners of a 2006 2350 with a slide and power couch. Few water leaks, and of the 'environmental' sort, not the potable/pressured water system.
Leaving the slide extended during a rainstorm we did get inside water soaking the carpet. Easily explained, it was a driving wind that caused it. I could see the droplets using a flashlight.
During pre purchase inspection, the dealer said the upper right marker light had leaked. They had replaced it, and re-did the headliner. It was a tad damp whenI did the pre purchase inspection, but was also a humid morning so not out of line. I could also see some black urethane sealant slopped here and there, and assumed a windshield replacement.
Well... the morning after we got it home, the DEW fall caused a 'puddling leak' on the center console and drivers floor.

doing a quick hose check, I found a generous leak. Ouch.
Turned out there was rust (from faulty/inefficient primer and paint from Ford...) that caused holes to form under the glass windshield trim. The dealer did a half-fast

repair on it, and never checked the work. Or did, and didnt give a rats derriere. I stripped the trim off the glass, and sealed the entire gully with black urethane. No mo leaks.

The right rear corner of the coach shows a leak, by wall staining and mattress staining. It has yet to be damp since we have had it, however.
The 'mystery' leak is the lower step of the doorway. the wood there was 95% rotted away, so i cleaned it thoroughly and put some cardboard under the linoleum to be a 'tattle tale.
I did see this water on pre purchase inspection, and was told that the sink drain had a leak that caused it. The fix would require the drain to be re-sealed. Not a big deal, I was comfortable with that task. Turned out the drain is fine. I did have to rebuild the sink faucet, however. f'n salesmen..
Well.. wasnt the faucet either.

... any rain (but not dew! ) will soak the forward part of the lower step, and seems to be up the carpet also. Staining on the carpet reflects this also. Not sure where this is coming from. I have yet to do a good 'hose check' however, and will report back after i do.
We are running a dehumidifier on its own cord to dry the coach, and it works well. I live in a humid area.

Anyone else have stories/advice on rainwater leaks into the coach?
Thanks!