1.) Brake tube nut:
If it's not already too late, go out and get yourself a set of flare nut wrenches that are made for this purpose.
2.) Brake leading / trailing shoe:
Sometimes the front and back shoes are different. The shoe with the shorter strip of lining usually goes towards the front.
3.) Brake Tube
Unless you are restoring this truck to a "numbers matching" level of original condition ... you can simply buy a $3.00 pre-assembled straight steel brake line with fittings at your local parts store. They are available in plain tubing or in spring armor wrapped varieties.
I prefer the spring ones as they not only protect the tube from abrasion and rocks ... they also help to support the tube while you bend it to prevent kinking. That is sill no substitute for a proper tubing bender if you need to make sharp bends ... but it does help.