Frank, as you probably know, those of us on AirForum tend to be very passionate about our trailering. My guess is the more time you spend with your Overlander the more you will become attached to it. And, fixing it yourself is very rewarding because you will know how things work. As others have already noted, the big vote for plumbing these days is for PEX (that stands for "cross-linked polyethylene"). Virtually all new homes use it, as does Airstream in their new trailers. It has a lot of advantages...including giving a bit of flex if it should freeze (unlike copper). Also, you fasten it using crimp rings and a special tool. There are alternate ways of fastening PEX, but crimp rings are the cheapest and most common. You can join PEX to other things as well, and Lowes and Home Depot have almost every possible part and diameter you would need. You'll also see that PEX comes in colors. I did a pool house and used red for the hot water lines and blue for cold water (duh). My suggestion to you is --- whatever you do -- do it right the FIRST time so you don't have to do it over again. I've learned this lesson the hard way. Too many times! Again, welcome to you.
"SilverLeaf II" 2015 30' Classic
2014 RAM 2500 Laramie 4x4 CC w/6.7L Cummins
WBCCI # 3430-Unit 21