I try and have things mostly cut and ready to sew. The main things I don't take are paper piecing and any actual quilting. Paper piecing just makes a huge mess and you generally don't have a huge amount of space to quilt anything very big.
To the last retreat I took a bed runner that all the paper pieced blocks were done and the rest just needed put together, a small paper pieced wall hanging that just needed put together and a shop hop quilt that hadn't been started yet. I got the bed runner together, the wall hanging together and all but 3 of the shop hop blocks done.