SKY,
GPS is a minimum requirement for both users and drivers. If you want to use a GPS dependent service, then you need to get a phone that has GPS. If you wish to drive for a GPS dependant transportation service, you too need a GPS receiver.
Thankfully the GPS system is maintained by those with the $$$ and technical resources to do so. It works reliably anywhere on the planet almost all of the time - damn those solar flares...
As for GPS directions, a small amount of common sense comes into play. The operator of a vehicle is expected to know a little about the area in which they operate. It's generally not a good form to drive through a river to get to a pickup location, a close by bridge across said river would be preferable.