I have about 1 to 2 hours or so each week to play piano, and not working towwards anything, just making sure my fingers don't sieze up.

If you had only 1 hour, what would you do? Scales and arrpegios? Studies? Play for fun?

15 mins scales/arps . 30 mins working on a couple of pieces seriously. 15 mins playing stuff you know well for fun.

If you aren't working towards anything, not having lessons and have not particular goals I'd play for fun but maybe try to be learning something new.