I live in wyoming and can tell you for sure dont count on your phone, service is very iffy! I use a garmin gps with the map program from LRH STORE
For my paper maps I use the standard blm maps and quad maps for better detail. If your hunt area is in an area where oil/gas drilling has been heavy, the roads wil be difrent than any map you buy, lots of new roads. The new version of the gps chip shows who owns the land as well, you can use this to know who to ask for premission. Good luck on the draw.