I play a location-based game called Ingress, which requires you to visit real-world landmarks and monuments during the course of the game. If you haven't heard of it, check it out (join the Enlightened), but if you have, you're probably here because you want to know if it's possible to walk the West Highland Way and keep your Sojourner achievement. Well, luckily, the answer is yes.
Below I include a set of maps from the Ingress intel site. There's 12 maps from the 12 towns you pass through, not including Fort William at the end (it's full of portals). On most days you will pass through at least one of these locations.
Note that you'll need to keep your phone charged to play, and this really isn't an issue. If your phone will a day on battery saver with the WiFi off, you won't have problems. Most days you can pass at least one pub or cafe for lunch/dinner and I had no problem charging my phone while eating. I also brought a small battery pack - light weight is best, 5,000mAh should be plenty. It's only for 'just-in-case'.
I haven't described each one in huge detail, so in the areas with only one portal be sure to check ahead of time each day.
Right at the start of the way is Milngavie. There's plenty of portals in the center where the walk starts.
Drymen is the target village for the end of the first day on most itineraries. There's some good pubs with portals in range, no problems here. It's a short walk off the way itself into town and then back again the next day.
Balmaha is not so well provisioned but the portals aren't far from the Oak Tree, a nice place to stop before heading on to Rowardennan.
I have two maps here. The top one is further South (i.e. you'll hit it first if you started from Milngavie), and the next shows a group of three portals just before the lodge.
One portal on the way to Inversnaid, where the river runs into Loch Lomond. Be careful not to miss this one.
If you got the portal passing Inversnaid, you won't need this one. This is the typical end of day three.
Three portals in the middle of the village for day four. Nice and easy.
The typical end of day four. A whole bunch of portals right in the way of the path. You'll pass them coming into town and then going out again the next day.
Bridge of Orchy
There's two portals here along the old military road. It's important to grab these if you're continuing to Inverornan.
Here is the first time when there's really nothing around. Luckily you should just be passing through and there are portals at Kingshouse.
Almost finished, the end of day 6. A whole bunch of portals here.
It's worth a note here that if you're looking at your phone at this point you're making a huge mistake. Glencoe is incredibly beautiful and there's some excellent views on this leg. There's also a bunch of portals in Kinlochleven to welcome you when you get there.