190, 191, 192, 195, 198, 199
Here is a link to a map with the busroutes. The trip to the MacDonalds will take roughly 2 strippen (being Dutch you'll know what I mean).
Another very nice spottersplace that can be reached by bus is the place near the Martinair Cargo fascilities. It is better than the MacDonalds. There are more movements and the sun is in the back. Moreover, you are just 100 meters away from the taxiway leading to the Martinair platform.
To go there you can take busline 191, and get out at busstop Reyklaviklaan/weg/straat something like that. From there it is about 10 to 15 minutes walking to the spot. I can not give you precise directions from there on, but if you have the map of Schiphol (such as the map on the link) and you know were the Martinair fascilities are, you will find it.
For more info about this spot look at:
The name of the spot is Officiele (off.) spot Kaagbaan.
When do you want to go to Schiphol? It is my holiday as well next week, and I was also planning to go to Schiphol.