I95 south thru providence. Take exit 9 (Rt. 4 south), I believe that it is a left exit.
Continue on Rt. 4 south for approx. 10 miles (I've been told my mileage from mapquest is wrong... maybe KKMatt will jump in here)... anyways... keep going on Rt. 4 south... runs into Rt. 1 south.. shortly after take exit for Rt. 138 east toward Newport.
Take rt. 138 east approx 6 miles (again, mileage from mapquest). You'll cross the Jamestown bridge along the way. Take the Jamestown exit (last exit before toll bridge).
Keep going straight off the ramp and thru the center of Jamestown (a mile or so). After Jamestown (approx. .5 - 1 mile) take a left at the sign for Ft. Wetherill. 100 yds or so, enter the park on the right and take an immediate left. Another 100 yds or so to the parking lot. If you find yourself in a parking lot with faded lines, an old boat ramp on the left, and probably some divers, you're there.
If you have a cell phone, PM me and I'll give ya my number, just in case. We're gonna be there earlier than 11, but I'll try and be out of the water by 11 and turn my phone on.