While you're waiting to have your RV pressurized to test for leaks, you can do your own investigation. You'll need a leaf blower, a section of plywood and some packaging tape.
Open one of you slide windows and remove the screen. Cut out a section of plywood to fit in the window opening. Seal it with packaging tape(or equivalent). Cut a hole in the center of the plywood, just large enough to insect the leaf blower nozzle. You may have to support the leaf blower on one of the rungs of a step ladder. Seal off around the leaf blower nozzle, where it goes into the plywood. Close all other doors and windows, exhaust vents, furness vents, etc..
Fill a spray bottle with liquid soap(dish washing liquid is preferred).
Crank up the leaf blower and, using the spray bottle, spray the liquid solution around all window seals, door seals, etc.., to check for possible areas of water intrusion.
for a basic example.