[cabinetman]

I would first use a nail set and seat those nails a bit. Then I would sand the top (150x) so you don't have those irregularities. You could use just about any finish once sanded...any of the wiping oil mixes, wiping varnish, or straight oil (BLO or Tung). If you can spray...lacquer, conversion varnish, or waterbase polyurethane.

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[cabinetman]

Would an oil or "just about any finish" fill in those little crack-like spots, where the splinters come from? I don't know much, but something tells me just applying another oil will create a nice look, but not actually create a long lasting protection that I'm looking for.

And as for sanding, should I use an electric sander and go over the entire surface?

I suggested seating the nails with a nail set. In using a random orbit sander (ROS), sand the table down to eliminate the loose wood sections. You can't "glue" the loose pieces down with a thinned polyurethane, as that would preclude doing any staining once dry.

Once the table is "surfaced", stain with an oil base stain, and then you can use a wipe on oil base finish like Watco". Or use a Watco that has a color you like.

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