score:5
Sloterdijk was a village out of Amsterdam but has now been gulped up by the city and is part of it. Just like the villages around London are part of Greater London.
It is within the city bus system area and on those buses you can use the travel passes for the city. And depending on where you want to be in Amsterdam, the bus might well be faster than going by train and take a bus from the Central station.
The OV9292 planner will tell you door to door, your hotel to wherever you want to go, how to get there. You can even set it to 'no train' to get that out of the results.
When you arrive you can ask whether there still is a bus pass that allows travel on the NS trains (national railways) within the Amsterdam area. I will look further and update if I do find one.
An OV chip seems a good investment but you need to realize that at the start of any train travel you need to have β¬20 on it, even for just a β¬2.20 'within the city' run. And it has to be a different OV chip for each of you, so as a couple you can be left with about β¬35 on your cards. Officially you can get a refund for that money, but it takes time and effort and you will always lose some money.
The Amsterdam tourist information office site has a list of public transport passes and non of them includes the train within Amsterdam, apart from the 'Schiphol return' which you already found.
An other site mentions renting a bicycle, which might suit you. It is cheaper than three bus or tram tickets per day, but it does include some effort. Riding is safe and helmets are not used by those using utility bikes as rentals mostly are.
Dutch cyclist do only use helmets when going high speed or off road, as a rule, that means that if you want to rent a bike and peddle on the bike lanes, you can do so without helmets, which makes bike rental much easier for tourists.
Helmets are not only not mandatory, they are also not often used.
Upvote:3
I don't know any other day ticket that would fit the bill but you can go from Sloterdijk station to many places in the city with the subway/metro or tramways and to Amsterdam Centraal with a bus. So the issue is one of commercial/administrative policy (trains are operated by another company), not merely the fact that Sloterdijk would be out of the GVB day ticket's validity area. It's certainly fully integrated with Amsterdam nowadays.