I assume your GPS problems are with the factory unit?
Sell it on eBay and buy a real one.
I don't know about the HD unit - check your manual, but most GPS units will allow you to route your trip in one of three ways.
Direct (dtraight line)
Shortest or quickest, which are not the same.
Shortest may be back roads between a and b, but quickest may be the highway, which may be why your GPS kept recalculating your route back to the highway.
And as you get better GPS units you can set them up to avoid certain items like toll roads, u-turns 1 way streets (which BTW the were first seen in New Jersey when the Morro Castle ran up on the beach).