The routes I take are somewhat dependent on the bike, but the fastest route on all three bikes is about 18 miles. On a dry day, some wind, on the road bike, (remember this is a Trek 1200, nothing special, on Schwalbe Marathon Plus), I can put 70 minutes to, 55 minutes from. The MTB, was a Cannondale F6 furio set up on Panaracer Dart Front, Specialized CrossRoads Tires, which are very road friendly, took 80-90 minutes to, 60 minutes from. The Trek Soho IGH on Panaracer T-serv Protex Front (Slow but great grip), Continental Travel Contact Rear, 90 minutes to, 65 minutes from, with full mini-panniers and a 1/2 full toolkit (so maybe an additional 30 lbs over the other two bikes so its not a completely fair comparison, with the ability to put on two garbage bag panniers.)

So unladen road bike with derailleur to partially laden upright IGH over 18x2 miles costs me 30 minutes a day minus 10 minutes maintenance differential = 20 minutes per day.

20 minutes per day x 4 x 40 or roughly 3200 minutes per year. So 2.2 ride days per year I gained, glass is half full, and so on, and so forth, big grin.