Owlie,
You will ride faster in a paceline, and enjoy the slip-stream. The line will slow on the hills, then reform. However, if being dropped will fustrate you to the point that it's no longer fun (you feel "abandoned"), or riding in a paceline is scary in itself, then I wouldn't do the ride. But chat with the ride organizer and find out about the ride, and the guys that do it.

Spin up the hills. Lower your gear and spin. No mashing.

(yeah right... Then there was the hill where I got off and walked because it was faster and I had a leg cramp. )