Originally Posted by nomad1972

As long as you don't have checked luggage you need to pick up at the belt, I don't see why you would have an issue checking in to the Aspire Lounge by Pier E (non-Schengen) for a few of hours before heading out through immigration. Unlike an airline lounge where they do demand to see a boarding card, all independent lounges care for is getting paid (ie an imprint of your PP card).

As for getting from Schiphol to downtown Amsterdam, your best bet is the train - you're there in roughly 15 minutes.