looked at that 4-30 post
the road side front sidewall corner indention is for the hot water heater
a 6 gal suburban fits right in it
mine was already there but it could be added easily to yours, gas right under it on frame rail, water going by to the toilet.
my window wood was also damaged, the 5 windows
on mine were put in dry, then just SILICONE around the frame. the Masonite ceiling was all bowed and sagging from holding water, that cloth wrap held water real good
i did put my rack back on but i put green wood under the holes while ceiling was out to run screws into, should do better than just the fiberglass they went into before and put dycor roof sealer under each standoff before a screw went in, the sealer would hold rack on with out screws once it sets up so hopefully it won't leak again
hope to get mine finished for the maiden trip this summer to get the bugs worked out and then a longer trip this fall