Here are some pics of my truck w/o the rack.
I had to pick up a 15 foot step ladder for a job, and realized that I didn't have space for it! I was sitting on the back porch one night, looking at the Dodge Caravan that I was going to get rid of (Scrapped), and had an idea. I took the roof racks off the Dodge, and they looked like a pretty good fit. This was a 91 or 92 caravan, and they only had the aluminium roof racks for one or two years. I don't know if the fiberglass ones would work.
1.You need to slide back the aluminum to access the phillips stainless steel screws that bolt through the racks into the roof.
2. mount the rack on your fiberglass camper shell. even it out and put marks through the holes onto your shell.
3. I phoned the camper shell company, and they said that it was fine to drill through. The shell was way thicker than I thought, like 1/4" thick!
4. Put bolts through from the inside of camper shell, with washers. I think these were 1/4"x20tpi. I used 2 1/2" bolts and nyloc nuts.
5. Slide the aluminum covers back on the rack. You might want to cut a rubber washer/ grommet the size of the foot. I didn't and have never had a drop of water in the shell

Anyway, you could probably get one of these racks for 20 or thirty bux at a junkyard. They're great because they have sliding rails and tie down points. I've put canoes, ladders, and lots of other stuff up there.

 

Looks good. It'd be nice if you could find about two more of the cross-bars..



GB :)

 

Thanks Bird76! The cross-bars slide fore and aft, so it hasn't been much of an issue. I guess you could buy two sets of roof racks and slide in two more cross bars, just take two of the mounting posts off when transferring from one vehicle to another,and slide in another set. Might set you back another $20 or so! (not too much demand for 20 year old Dodge Caravan roof racks, I don't think) I have to give it to Dodge though, they design a nice roof rack...shame about their trucks!

 

Looks OK but two things…
Support for the fiberglass at the mounting points and the sides under the mounting points.
Tie downs, if the underside of the mount isn’t supported and through bolted then I would tie much to the rack.

Thinking out loud again !

 

There are two bolts per corner, 1/4"x 20tpi by 2 1/2" stainless steel. The bolt head is on the inside of the canopy. There is a large washer between it and the fiberglass. The bolt protrudes through the black resin mounts of the roof rack, and this is where the nylock nut threads on, to be later covered with the aluminum cover. I phoned the manufacturer before drilling. They stated that there is no strength concern, especially with 1/4" holes and washers being used, as they do it regularly for side mounting brackets for removable roof racks meant for cars with gutters. (TBH, I was actually kind of surprised they said go for it, but it made sense after I drilled the holes. The fiberglass is a lot thicker than you would think.) My canopy is stored by being hung by these corner mounts, and the canopy weighs 200lbs. There is absolutely no concern with strapping things to this rack.
That being said... nothing like a nice rack!