My wife (Maggie) & I spent 9 years living off our skills (Florida & Bahamas).
AC-Refr IS an EXCELLENT saleable skill, as are all marine
I started out a master electrician, but gradually expanded my expertise to include plumbing
, hydraulics, rig & structure, and outboards, etc.
curve is very steep! I started out thinking I was an expert; but after 13 years intensive experience & learning
; know I've still much to learn about marine
trades, especially including my base skill (electrical).
We lived-aboard a C&C29, which made tools & parts storage
(at sea) a major problem.
Notwithstanding space/weight limitations, take as much inventory as you possibly can.
My AC/R experience is limited to power & control (the elect. side); but suspect most problems involve gas. You'll want a good guage set, vacuum pump, and a supply of Freon (was still avail. in Bahamas
1999), soldering, multi-meter, & etc. I'm sure you'll know, better than I.
Not to forget your "rolladex". Being able to put your hands on parts
(often shipped from "Staeside"), and being able to pay for them, can be (in itself) a saleable skill. I maintained accounts, and relationships with the best resource-persons, at several Marine & Industrial supply houses - had I more contacts, I could have kept busy as a parts-acquisition broker.
Hope this has offered some (small) help & encouragement.
Good luck & regards,