Do it right.. and do it ONCE Mark ! Plan for three times as long as you think it will take.. and twice the money. Is it financially viable or are you putting money into a dark hole? All things I'm sure you have considered, but if you want a project in the garage and have another boat to fish from... why not!
Two options on the exterior... TAL STRIP II for aluminum and it's gonna take a few gallons ($45 per) or have it SODA blasted clean. You have to do the stripping inside.. no wind/etc or it won't work properly.
Once bare...You can scrub it down with Alum Prep to etch/clean it, but not extremely necessary with today's paint and self etching primers. But for what it costs for a jug I'd wash it down with it...while scrubbing with a white scotchbrite pad (and rubber gloves!).
Lunds are painted with PPG Concept or what ever the latest version of that is. Many paint shops run a PPG paint rail and can help you out. Use PPG's self etching epoxy primer for aluminum.. spray on a coat and then top coat within 24 hours, I believe it is, (or you'll have to sand before top coating!) Same deal between colours if you are adding accent colours.