Wow you sound like you are in great shape to me. Working out like that three times a week sure seems to be more then you would get from riding a bike? Maybe you don't need to do any extra.
We setup one of the bedrooms with a treadmill, ski machine (kinda like spinning), an AB Lounge, a rolling wheel, jump ropes and some of those things you mash between your legs.
We got so tired and bored of looking at the walls while working out that we added a TV and a DVD player. Tried three fitness centers, I must be a magnet for the nut cases who all think I want to be in as good of shape as they are in. Or that everyone should be impress that they could bench press a pickup truck with a car in the back.
I think it is best to just put on a jacket and go take a walk or any time I see a nice day I will go take a ride.
Keep up the good work..