It really depends on your personal goals. Do you have a set distance you'd like to get to? If that's the case, then I'd try to add more mileage at a pace that pushes you a little bit.

Are you working out with a heart rate monitor?

I have one ride that I consider my training ride. There are specific points on it where I just really hammer for all I'm worth, whether I'm on the single or riding the tandem. (Poor Thom I really pushed him on it this weekend. Work has kept him off his bike for a few weeks.) The rest of the time when I ride, I try to keep my heart rate in my high endurance range and just enjoy being on the bike.

V.