That’s what we’re here for. Just post a question and someone will usually have an answer. Or comment, opinion, anecdote, suggestion, rebuttal, …….
I’m 2 years into a rehab my 3rd Vintage trailer, a rescued ’72 Tradewind.
If you’re planning on repairs or upgrades may I suggest picking up a repair manual. I purchased mine off e-Bay from a vender in Canada. vox231 | eBay
The one I got has the owner’s manual included on the disc. Looks like he’s got one for the ’73.
As far a plumbing goes it’s an issue for most vintage rigs. Mine was a mess as well. Replaced the front half last winter. It’s a topic that brings a wide range of opinion. Ask away.
Good luck, have fun,
Heres a screen shot of the plumbing in a '72 Overlander.