I'm in a similar boat.
Landing at LGA at 11 AM, flying out of JFK at 11:40 PM
I have a roller and a back-pack, so I'm looking to store the roller and go down-town.
No lockers or storage at Jamaica Station, unfortunately.
Should I take a cab down-town, store the bag at a storage site in Manhattan, then go from there to JFK after supper?
It doesn't seem to make much sense to go to JFK first to store it there.
Any other thoughts?
TIA