Re tethering... Try and see if that works...
Otherwise, a wifi only iPad would need an external GPS receiver... those can be had... BadElf makes options... Garmin has one... there are others...
Apps... The stock Apple Maps app works quite well for me - that can be used if the wifi iPad is tethered to a phone to fetch maps as needed... or - search the app store for an app that loads full maps onto the device so you don't have to rely on tethering for map data... Navigon is one such app that I've used...