A few weeks ago, we took a long distance day ride leaving out of Pleasanton, where my Grandparents live. We loaded up our bags to near capacity (35-40 lbs) and did a 4-hour trip around the paved and non-paved backroads of Poteet, Jourdanton and Pleasanton. We averaged about 10 miles per hour and took a break every hour for a Clif bar and a stretch.
By the end, our derrière's were pretty sore, but we were pretty satisfied with our time and distance traveled.
Now we just have to prep for going up near vertical hills and riding through metropolis's chock full of rickshaws and scooters.