I’ve done a bit of re-finishing, and I had a killer back-ache, as the 100# sander was designed to be used by people shorter than 6’, so I was constantly stooping to hold the handle. If you have a free weekend, you should be able to get it done, if you have minimal DIY skills. Also, consider that gloss finish will show flaws more than satin. I think both look nice.
I helped my mom refinish the bedroom floors in our house when I was 16 (she’d had professionals do the rest of the house). In addition to putting lots of minor divots in the first floor we did (we got a lot better with practice), we managed to start a small fire when she pulled the damned electric cord for the sander directly into the path I was sanding on.
Sawdust burns real good, in case you’re wondering. I’m just glad that we hadn’t started putting down the finishing chemicals, yet; the whole house would’ve gone up like a roman candle.
That was one of Mom’s more successful home improvement projects, come to think of it.
I’ve done 3 houses myself (with a buddy). Total of 8 rooms and a hallway. If you don’t mind starting on a back room you don’t care as much for, until you get the knack, then I think it is a DIY project.
Expect 2 or more weekend and a lot of dust to get the job done.
I started with a rented drum sander. Long, slow passes, coase, medium, fine. Then used a rotary buffer with coarse, medium and fine screens. Used a small hand sander for the dges and corners.
I do not reccomend any kind of poly-whatever. Danish wood oil looks better, is easier to apply and lasts longer in my opinion.
Good luck!