Almost impossible. There's a tiny access panel on one side so you can reach the pump and electrical junction box...barely. Not hardly big enough, in my opinion. Suppose I could always make that opening bigger.Anyway.. I'd see about doing multiple Ahh-somes on the jetted tub or even pulling lines on it (which may be far harder than the hot tub, I've never had one). The good thing is once you clean all of that out well, you will maintain it properly from then on, so you shouldn't have to ever do it again except to fix issues. Good luck with the move. Enjoy.
Some things can be reached from the basement, as one end of the tub is on an open wall on the basement side. Not sure how you could reach any hoses/junctions in the middle sides of the tub though.
I'm not even sure what maintaining a jetted tub entails. You don't use chlorine. Water probably sits in the plumbing when you drain it. Do you add bleach before you drain to kill most things that may be in there? Do an Ahh-some purge before each use? Honestly it seems kinda gross no matter what, compared to a spa that's always filled and maintained with chlorine or bromine.