Bathroom vanities - refinishing

I'm replacing my bathroom countertops with Corian, but decided to keep the original vanities. I'm looking for advice on refinishing them. Any ideas about the original wood or finish? The house is in Upper Lucas Valley, built 1964.

One of them appears to be the original finish: a dark stain with a clear finish. The finish is beat up in places with the light wood showing through. I wonder if I could lightly sand to rough up the surface, spot-stain the light areas with a water-based stain (what color??) and then finish with water-based polyurethane.

In the other one, the original finish was painted over with some kind of lighter color to look like faux wood grain. Even the slider grooves were painted. I hate to strip it, should I just paint it? I could use a medium brown like I have on the beams.

Then, what to do about the doors, which have been painted. What kind of paint will still be able to slide in the grooves? I saw a post a few months back about using new solid surface panels for the sliders. Anybody tried this?

Any advice in this area is appreciated.