I loved Delorme street atlas, greatest software out there, but the delorme GPS was made for walking, or you could use your laptop.
Than Garmin bought them out. I have spend a lot of time switching to Base Camp.
the trick is to first make sure your GPS and base camp are both set to the same routing method, (shortest, fastest, etc). add some way points in your route, then load them to GPS and view the route, is it what you expected? Remember all you are doing is sending way points to GPS from base camp and the GPS is creating its own route from way point to way point. All you can do is keep adding way points until the GPS routes you were you want to go.
another problem I have had it my Drive series receives traffic data and can route you around an accident, but if you have a way point near the accident the GPS will still be routing you around the accident to that next way point, not your true destination.
With every GPS, you have to visually run a sanity check on every route before you leave. If this is a a route somewhere I have never been, I might have one line paper notes about major turns that I expect. If GPS starts to route you somewhere else, make that turn you have on paper and GPS will re-calibrate.