I purchased a Don Hill 13' drift boat a few months back and have been sanding the heck out of it and trying to bring it back to some semblance of its original beauty. Feel like I'm finally getting there, but I have a few questions on some particulars regarding staining the interior. 

First, I was told Cetol Marine is a great way to go for most of the interior. I've begun to apply this to the floorboards and I love the look it gets. My question is: is epoxying the int. floor the best way to go? I have a System Three spar varnish as well. Could I go over the Cetol with that, at least for the bottom to give extra protection? I heard that varnish tends to fade and crack quickly, though I wonder if this is only to do with leaving a boat uncovered and exposed to the elements for long periods of time. And, since I'd be covering up the bottom mostly with stained floorboards, would this still be an issue? So, epoxy over Cetol, varnish of Cetol, or just Cetol? The sides seem less an issue, since less water can travel through there, and therefore it would make sense simply to use an oil stain like Cetol or some other one.

Next, it seems like I've seen a lot of conflicting information on here, and on other forums, about what type of paint to use on the exterior. Sure, ideally I'd have loved to have gone with a clear varnish or epoxy, but since it was already painted and such, that seemed perhaps futile, or at least a tremendous amount of extra work. Some people seemed to suggest that using a very high-grade exterior paint (non-marine) is totally fine and you can just lightly sand and add a coat or two each year or so. Correct me if I'm totally off on this (though it would be too late, as I've already gone this route). Either way, I'm just curious for future reference and future repainting.

Any advice or other tips are greatly appreciated.