But kinda nice.
Did you say you used silicon to mount those windows
Silicon can dry with cracks in it or can get mushed out when installing the window allowing water to flow .
, as far as I know,and any other doors should be mounted to the outside wall of the camper with butyl rubber tape. This stuff comes on rolls of 3/4 " wide and is sort of nasty feeling, like putty, but easy to work with ( unless its really hot out, then its gooey).
Costs about 4 bucks a roll, can get it at any rv place.
Just put the tape flat around the flange of the window( don't stretch it) overlap at any seams. Mount the window, screw in the screws which will make some excess tape ooze out on the outside wall (this is good). trim off the excess ooze with a plastic or wooden stick.
This stuff will also fill in any slack from ,say ,a wavy fiberglass wall.
Window flat + wall wavy = leak point.
Then for good measure you can run a bead of rv stuff I forget the name ( something like r440 ) ask the RV guy, around the edge. Its like a super silicon, comes in white.
This stuff is also good for sealing all the wire holes from the running lights
and tailights, another source of leakage.
The above has made my Burro