We just did this last week. Get to the GRP lobby about 6:45. Tell security to call a taxi for you. The cost is $13-$14 dollars one way. Make sure you tell the driver the street locations, because most don't know where the restaurants or coffee shops are. Our driver let us out at the corner of 10th and 10th.
We were picked up by Eder at 7:30 at Java Joe's.
P.S. Hang on tight in those taxis!