Not sure what would show up on the GPS, but it's not too difficult to find. My brother tried to use a GPS and wound up way lost. If you come down 127 across the dam, it's pretty easy. If i recall there were signs marking the way from 127. We did it in the dark, boat in tow with no problems.
If you are planning on towing your 38 to Grider be careful around the marina. I ended up infront of the lodge with the rig, and there is not an easy place to turn around. Be sure to follow the signs to the ramp. It is quite steep and twisty once you get on the property. Enjoy it!