Have you read Don Casey's "This Old Boat"? It won't help you diagnose much, but it is helpful for helping you figure out the how to's once you identify what projects need done.
The first step, if you have the space, is to take everything out of the boat, so that you know what you have. I am so glad we did this because we found an open bag of rice and a handful of crackers - luckily, no bugs on them! Since ours wasn't a total refit
, we also deep cleaned everything, scrubbed the bilges, etc.
Start a list of projects. Prioritize them by what keeps the boat afloat, safe, sailing, and finally comfy. Also, make a list of what projects involve tearing the same cabinet apart so that you only have to do it once.
Will you be working on the water
or on the hard