I've made fairly easy work of mounting racks to road bikes also. I think of all the modern braking systems, disc brakes provide the biggest hurdles for someone installing a rack, but here are workarounds available.

Some bikes can be tough to get fenders on, however. My old Univega Super Special and Trek 400's fork, brake bridge and calipers allowed full fenders no problemo. My Pinarello won't even fit 28mm tires, let alone 23s and full fenders. I run a backscratcher in the wet, just to keep my butt and backpack clean and mostly dry.