Thanks for all the connector help below. I've decided that it's all useless :). Just kidding, but after someone pointed out that a 15' rail would fit on a car, I decided to just build it all in one piece.
Now I need to figure out what kind of metal to use. I thought all park rails were built out of 'hardened' steel. But after calling a bunch of steel distributers here in SLC I learned that hardened steel doesn't come in pipe form.
So is it hardened steel? Like with an AR coating (for wear)? Or will regular steel (grade 50) work?
Park monkeys -- speak up!