Cannot advise on relative merits of the two RLDs.
Den Haag is approx 45 minutes by fastest service from Amsterdam, note that there are two main stations there - HS and Centraal - with
different direct services. RLD is a short walk from HS, a bit further from Centraal. Return to Schiphol, from either station, is approx 30 minutes.
Alkmaar is not so far from Amsterdam - approx 30 minutes - but further back to Schiphol - approx 45 minutes.
Go to
www.ns.nl for detailed schedule.