I was recently in Netherlands for a couple of weeks..
I contemplated doing the SIM card thing (I always buy my phones so that they are not locked to a carrier), but I instead chose to do AT&T's 'international day pass'. It is a bit expensive at $10/day.. but it's capped at 10 charges per billing cycle. So that wound wind up being $100/month. using a SIM is quite likely going to be cheaper, but the convenience of the AT&T thing was nice. Didn't have to figure anything out :). And you would only get charged for that day if you actually used the phone (so if you didn't want the charge that day, you switch to airplane mode)
One thing that I think is pretty slick is an app called Pocket Earth. I think it costed me $8 or something several years back. I did an entire week long trip in Ireland without having any cellular service. Drove around the entire country.
I would get the offline maps with this app and directions for my route that day while on WiFi at my B&B. It was better than getting google maps offline because you can just download the map of the country whereas google at the time, I would have had to take a dozen hand drawn 'snips' in order to achieve the same thing.
You don't need a cellular connection to use your phone's GPS, only to load the maps.. which is why this app works like it does.
Downside to this method, it can't recalculate your route if you deviate. But you can still figure out how to get back..
