Adding onto the no credit card issue. Almost all US hotels place a hold on your account for an amount they determine to cover possible incidentals. This can range from 20$ to a full night's charge and sometimes more if the room rate is low. For credit cards that isn't much of an issue as it just decreases your credit limit until the hold is removed. But with a debit card this removes your actual cash temporarily from the card and can take up to 10 days to appear back in your account. I'd suggest getting a credit card if possible just for this purpose unless you have a large amount of cash and deem this unnecessary.

Also remember to check if you can access the location of the lounge that PP or the membership provide. Just because there is a lounge at JFK doesn't mean you can get to it. Not all airports allow you to access any terminal you wish or have connecting airside terminals.