roof racks for 2002 windstar lx

I just picked up a 12 foot aluminum fishing boat and need a way to get it home. I kinda planned on fashioning a simple roof rack system out of a few 2x4's that I could attach to the rack track with a angle bracket. A carriage bolt/wing nut would attach the wood to the roof rack track slot and then of course tighten the boat down with strapping and rope at the front.

I have a tent trailer that I plan on carrying it usually...this is just to get it home from where I'm buying it, and if it works good then may be use it to head out for day fishing trips that don't require the tent trailer.

I am just wondering if anybody else out there with a 2002 Windstar ( or similar) with those types of roof racks have ever tried to put a small boat up there (12 foot). I currently pay for a storage spot for the tent trailer and if I ended up having to get a small trailer to cart the boat around, I would need to get a bigger storage spot (more $$$$).

Any thoughts/ideas welcome.