Riding about 250 miles per month on a 29er and old Trek carbon road bike, right now predominately the 29er, as I stay off of the roads while the snowbirds are in town (Scottsdale). Want to get a new bike, my 29er was strictly entry level and my road bike was fairly expensive when I bought it but its 15 years old. My goals are really exercise, continued weight loss (down about 25 pounds) and builidng endurance. I lift at least three days a week, fairly heavy as I don't want to lose all my muscle at my age, 62. I've looked at straight bar road bikes, Specialized, and normal road bikes, but am also considering an upgrade to the 29er. I love the fit, feel and control of the 29er, but can't see trying to ride a 35 pound mountain bike 70 miles. (My only real goal is to do the Tour de Scottsdale this year, 70 miles I believe). As you can see I'm totally confused as to direction to take and bike to buy. Anyone have any thoughts other than to tell me to make up my mind before I go looking?