A rope "Ladder" of PVC perpindicular to the hulls will allow you to easily slide your boat up the beach. My friend(who is in his 70's) slides his SC 20 up his beach with no damage to his hulls, and they are HEA-VY!
When your boat is in the spot where you want it, fold up the PVC ladder and you're done.

Bill Hendrix at Mainsail marine in Greenville SC also makes a small sandbag out of Sunbrella? that slides as easy as anything Ive ever seen. Just keep moving the sandbags while you are sliding your boat, and either empty them and take them home or leave them filled. It sounds crazy, but it really worked well. The bags were approximately 8 inches in diameter by 12 inches long. I think the material was the key, but I cant remeber what they were made of(maybe a trade secret too)