Some potential interior leaks points (I've had all of these once over the first 14 months):
1. If the kitchen sink is in a slide-out, the water and drain lines are of a flex, not Pex type. In my units not long after delivery, I had a leak under the kitchen/entertainment slide out onto the kitchen floor. It was the sink drain line causing it in mine. In some early Landmark units, a very rigid hose was used for the piece that slides back and forth. Later, more flexible hose was used. Mine kinked due to being too rigid which caused a backup which caused a leak at the transition into the PVC nearer the sink.
2. The kitchen faucet that is the pull-out sprayer type in my March-2005 built Landmark developed a leak in the spray-head area where the metal head threads onto a plastic piece, then the spray-hose threads onto the other end of that plastic piece. Under use, water would leak and seem to travel down the hose, under the sink and onto the floor and out into the open. Received a warranty replacement faucet and installed myself.
3. If your refer has an icemaker, the water line feeding it is tapped (teed) into another water line in the basement and feeds a 1/4" plastic line un into the back of the refer accessable from the outside only. It connects to the water solenoid (electric controlled water valve), then travels up the back of the refer (disappearing) and into the top of the refer to feed the ice maker. At the rally, Holmes on Wheels pulled my refer and found that Dometic was missing a brass collet in the line where the line connects at the top of the refer causing an intermittent water leak that was running out onto our kitchen floor.
N.o.n.e. of these may be the cause of your entertainment slide leak but I figured it may help others who have a small but pesky leak they have not yet tracked down.
Please let us know what the cause and fix for yours ends up being.
Jim
PS: I just realized that on this forum, you can't use the word n.o.n.e. because it is the code for the Angel smiley. That's crazy. I'll be looking into it.