I have been to several retreats. Here are my suggestions:
Skip the games. Especially if they are physical. There are a lot of older women at the retreats I go to that can't do physical games and felt left out.
Show and Tell. Have everyone bring one of their projects and show off. I think it is one of the best parts of the retreat.
White Elephant exchange. Everyone brings some unwanted quilting supplies in a package of some sort. Then whoever draws #1 picks a package and opens it. #2 can either pick one out of the pile or take #1. A package can trade hands 3 times then it is dead. It can be a lot of fun.
Seret Pals. Bring a bag of small items to shower on your secret pal. Drop them off on her sewing machine several times during the retreat then everyone meets their secret pal at the end.
Plenty of time for sewing. The ladies who put on the retreat are always walking around talking or helping with questions.
Make sure there is a lot of coffee and drinks and TP. My last retreat we ran out of TP. With 30 women drinking coffee that was a disaster.
Have fun. Even if you just sew and talk and eat you will have a good time.