The top is about one inch thick of solid wood. Around the edges there
are three inches of thickness of the same boards.

Would you please give me some sincere suggestions?

I don't think you're going to be able to just go out and get a 36"
planer for one job, unless you really planned well for your
retirement. My advice would be just to go get yourself a good random
orbital sander and sand that sucker with 60 grit until the scratches
are gone. Change your paper frequently, and it shouldn't take too
long. Then work up the grits to whatever finish you feel comfortable
with (I'd say 220 grit as a minimum), give it a coat of sealer, stain
it, then clearcoat it. You've got plenty of wood there, and you said
you've got the time, so I would imagine that is the best way for you
to go.

Aut inveniam viam aut faciam