Re: welding and welder options
I don't think that using an inverter as the power source will work too well. Alternating generators struggle to power arc welding equipment that generally have very high inrush currents. I suspect most inverter welders have relatively horrid leading power factors which won't help either. Ring up Lincoln technical support and ask them for final verification. They will have a definitive answer for you.
On a more general note, you need a decent MIG of at least 200A for your auto / trailer / initial boat work. Either get a combo inverter stick/TIG welder as a companion to use once cruising on the boat or trade the MIG for one when the time comes. You might also consider that some combo units now also include a plasma cutting option as well although these will be getting up a bit in physical size. Having said that, if it were me, I'd get a simple inverter stick / scratch start TIG for storing on a boat. This will allow welding of mild and stainless steels with stick (on a side note, I think stainless is easier to weld than mild with stick). For smaller cutting jobs, a thin cutting disk on a 4 1/2" grinder is hard to beat.
Just for interest, Oxy Acetylene welding, while versatile (it can weld and braze just about all metals including aluminium in the right hands) has a lot of disadvantages. The most significant is that it has a very high heat input when fusion welding compared to other processes. This means that materials with high coefficients of expansion like stainless steel and aluminium will distort like crazy unless done with some skill (TIG suffers from this as well since it is "electric oxy"). Stainless steel, in particular does not like to be kept soaking at certain elevated temperatures otherwise it suffers from "carbide precipitation", which is bad (google will explain more on this)