My cyclocross bikes like many others have a single ring up front because it's simpler and usually if you drop a chain it's from shifting the front or bouncing it off. It's less likely to loose a chain on a properly adjusted cog set. I use 8 speed in the back. I live in the mountains too and have a fixed gear ratio just good enough to get over 80% of the climbs. Some are a real struggle but others are OK. It's a bit of a trade off and it's excellent training for strength and a hell of a lot of fun.