[travelin texans]

#1 not vented outside is fairly typical on entry level RVs, not sure about adding.
#2 take vent trim down & check for wiring, could get power from a nearby light fixture.
#3 take the cover off, in 7-8 years it may just be full of dirt or ruined by the sun. As for LEDS that's your choice to add or not.
#4 no ladder usually indicates not walkable, also typical on entry level rvs & wouldn't add one, buy a portable to reach what's necessary & use a couple 2'x2' pieces of plywood or foam to spread your weight if on the roof.
#5 & 6 with a little ingenuity anything's possible.