I'm making a state park trail map for public use. In trying to decide what grid lines or tick marks to put on the map, I am having trouble deciding whether to use UTM NAD 1927 or UTM NAD1983 (WGS84). (I'm also going to include latitude/longitude tick marks).

Which is more commonly used by people with recreation-grade GPS units? In the map area (Blue Hills Reservation, Massachusetts, USA) the same coordinates in the two datums are shifted by 750 feet. The 2015 USGS topographic quadrangle uses NAD83/WGS84 (the 1985 map uses NAD27). My inclination is to use NAD83 but I haven't personally used Universal Transverse Mercator coordinates to navigate with a GPS unit so I'm not sure what the standard datum is.

The grids or tick marks will be used by some hikers and by public safety workers (park rangers, police, fire) if they need to search for a lost hiker.