As a scrapbooker, I just want to come and crop. I don't like to be bothered with games, etc. If there are drawings for free stuff, then I'll put my name in. My best friend and I usually attend events like this together and we'll share a table.
I do recommend selling drinks and or snacks for those people who don't bring their own.
Be sure to delinate each person's table space at the crop. Some people are table hogs.
Have lots of trash cans or paper recycling bins scattered around.
You can have consultants (Creative Memories/Close to my Heart) etc there but most people who attend events like this already know how to crop (or have their own consultant) and have their own supplies, tools, etc. You might ask a local scrapbook store (assuming there is one) to bring some fliers for people to take. Same thing with consultants.
Good luck! I think this is a great idea for fundraiser.