i know of a couple of places you can put in on the rapp near frederickburg. one is right in town, take route 17 bypass east to route one, make a right, go across the bridge and make a left at the first light, park and boat ramp is on your right. another choice (mine) is to get off at the mattoponex exit on the other end of town, make a right at the light and go down to the 17 bypass, take that about 10 miles and you will see a country store on the left. stop and pay for the launch, the boat ramp is about two miles behind the place. there is another ramp near the 30l bridge further down route 17 also. i have never fished for the large cats there, but i have caught a ton of channel cats. wish you luck.