Can Garmin Mobile PC give an alternate route?

There are so many experienced gps users here; forgive me for my ignorance...I used my Mobile PC for the first time, and it directed me to use a country highway in Ohio that turned out to be closed down. The highway detour signs were very ambiguous, it was 100 degrees, and the afternoon sun rendered my screen almost invisible. The gps kept trying to get me back on the deserted highway, and I did lots of extra driving before I was able to get myself home. How could I have gotten the gps to guide me home via an alternate route? There probably is an obvious solution, but not to me. Thanks if you can advise me!
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