If you have wi-fi only iPad, you will not have GPS built in. If you can't get that Garmin to hook up with it to provide GPS data, then you should consider a Bluetooth GPS receiver, such as the Dual XGPS150A
http://gps.dualav.com/explore-by-product/xgps150a/
Or better yet, take that new wi-fi only iPad back and buy one with wi-fi+cellular, that way you would get the GPS chip built in. You would not need to use the cellular data unless you wanted to. I have discovered that the Apple SIM which can work with any carrier but Verizon will constantly bug you to pick a carrier (and cellular plan.) I replaced the Apple SIM with a SIM from AT&T, though I did not activate a cellular plan, and at least it would allow me to turn off the cellular radio and stop bugging me to pick a carrier. (The Apple SIM will not allow you to turn off cellular.)