Welcome to the forum.
Well, you have many options, of course some more costly, others more labor intensive, etc. Given you don't have a lot of area to cover or work with in this puppy, what many do is skin the flatter areas with 1/8" plywood and trim it out with solid lumber, like a 1x2 or possibly smaller. A common "upgrade" is to make a filler piece for the V berth, which is usually little more than a 1x2 "cleat" for the plywood (3/8" - 1/2") to land on. Over this is a cushion. The aft side of the filler usually has a hardwood fiddle of some sort. The companionway area also often sees some treatment. There are many ways to approuch this. Your skill sets and tools often govern how and in what materials you'll proceed. You can use high pressure laminates (Formica), carpet (looks cheap), fillers and paint and countless other approaches to this. The keys to success may be, what can you do, what do you want, finish types,net results based on skill sets and budget, etc. Lastly, be honest about your skills against your desires and also about weight. Excess weight is a small boat performance killer and it usually doesn't take much, so keep this in mind while dreaming up what you'd like to see.
