Right now I sit in AMS.
Radamfi is right-this ARTT (quite costly though, but 3 days is reasonable-33 eur or so, which is in fact cheaper even for someone doing daily travel on a monthly on longer distance) DOES cover ALL connexxion buses of the concession Amstel&Meerlanden, incl this 397-a superfast (mostly reserved buslanes) via Airport (where it stands very long and usually gets filled to the brims with screaming tourists) into centre of AMS=busstation Marnixstraat, along Leidseplein. Mostly artic brandnew all-electric buses. This route even has its own website.
There is NO other ticket available that would cover it all. However, depending on your actual travelneeds, a cheaper priced just ATT + daily returns to Schiphol may work out better. Also: I am not aware of any HTL near to NwVnp station (which is in a bleak meadows-outpost), so I guess its in centre village, near the canal-and thus much closer to the bus.
(the region south of Amsterdam is covered by this concession-incl. towns like Aalsmeer, Hoofddorp, Uithoorn and the whole of busway 300 Haarlem-AMS/Bijlmer).
best info is on the site of gvb.nl -use /en/ then search for tourist offers. CAN be bought at S'hol from some AKO-newsagents or the Connexxion van near the inbound stop of 397 (If going first to HTL-use stop other side outbound) oir if you can brave the Qs from the NS-salespoint-NOT from any machine.
NOTE: we have this silly system where the pax MUST check in (thats how touch in is called here) AND OUT anytime from any trip made-which is thus other as Oyster/London. Your ticket can block if not done properly. Or you can be fined when a -very rare-check is being made without having properly checked in in THAT vehicle.