I'm seriously looking at the Cannondale Cyclocross. I think it's a solid bike. I will use it for serious road miles, some hills, commuting, and occasionally off road. Being a little uninformed about this new dimension in cycling, the double ring troubles me. It has a 38/46 double ring; SRAM P950, 12-26 on the back end. Will I get a real workout if I take it for some serious roadwork? (Most road bikes come with a triple, 52 being top end.) What about hills? Will I need the smaller third ring? I'm about to drop $1000 on sale. If a real road workout and solid frame is what I'm looking for, is this a good choice?