More to the point:
As NY pistol registration process is brutally slow, most gun shops have a hold-for-small-fee system in place.
(by 'shop' I mean just that. not gander mountain or whatever chain, but a privately owned mom-n-pop type business)
Perhaps an arrangement could be made with one so that for a few bucks a month he'll sit on your stuff in a very secure gun shop, and you can get it out any time he's open for business.
However, if you take that route you'll want photos, serial #'s, a very specific contract, and if at all possible, insurance so that you don't lose your propety to a 'whoops, accidentally sold it' incident, police raid for whatever dumb reason, or outright robbery of (or by) the shop.
You want to be able to unqustionably identify your proprerty and be able to obtain it within reasonable bounds without hassle.
'Reasonable' would be hours of operation, same day, not 'we need 2 weeks notice and you have to show up on the second Tuesday of next week between 26:00 and 26:08'
That may neccecitate picking stuff up Friday for use Saturday then drop off Monday if shop isn't open on weekends, but sitting on them for a weekend isn't too big a hassle I'd imagine.
Plus it would givwe you the time you desperately need to clean and familiarize with what you've gotten hold of.
Regarding insurance, check out renters insurance if you've not already.
Fairly cheap, and can cover a lot of things in the event of theft or damage from (insert incident like fire or whatever)
Nice to have in general, but very useful should you decide to keep the guns in the residence.