Ed,
I've done a few of these type projects so I'll recommend a Kregg jig. Even the cheapest one will make a lot of this type connection a fast and simple task. Combine that with a little glue makes a stout joint.
And as Norm Abrahams says, "You can never have too many clamps".
I spent 2 months working on my first TC before we could use it without getting wet. But when you get it done, you know what you have.
I do understand that feeling as you start that simple little task and find more and more issues.
You mentioned using angel steel or aluminum down the wing, that is how my AF is assembled. It runs almost the whole length of the wing.
Also, Glen-L sells camper plans that will give you insight into how some campers are assembled, but not necessarily how your TC is made. Might be a bit easier than "hauling a junker home". They have a small set of plans (17x22) as well as the full size set. Not sure if they will sell them separate.
My brother built their "Grandview" and then a 5th W many years ago.
Good luck.