The Trek X01 cyclocross, Lemond Poprad cyclocross, and the Trek Pilot series also have more comfortable geometry than a typical race bike. The Pilots are much lighter than the cyclocrossers and the Portland, as they use standard road brakes, vs. discs. Disc brakes are fantastic in bad weather, and especially offroad, but I'll take standard rim brakes on a road bike any day. Trek make the Pilot in both aluminum and carbon versions.
A local guy, who I occasionally mountain bike with, traded running for cycling @ 65. He built a web page about log jumping and winter riding when he was 69 or 70.
Thanks!