Ponchos are big sails. Fine when the wind is behind you and faster than your ground speed ... not so much the rest of the time.

Wool for me. I probably sweat more than most people, but I have yet to find anything (including expensive "breathable" gear) that doesn't make me just as wet with what it keeps in, as it would with what I'm trying to keep out.

A light wool base layer and synthetic fleecy knee warmers were just fine for me on Columbus Fall Challenge last year - <scurrying back to SportTracks to see exactly what the weather was, besides wet> steady temps in the low 60s all day both days, rain varying from heavy to light. So yours might be a bit cooler, but if it were me, I'd just wear a heavier wool base layer and possibly wool tights.

If you really want a rainsuit, then I'd go for Frogg Toggs spun polypropylene. It's about as breathable as it gets, very lightweight and relatively inexpensive.