Space cowboy, you sound like me. I've got two boys, a very physical job and a wife that works full time. Finding time to ride is difficult, and so much of the time I am just too tired. As the days get longer I try to ride in the early evenings, even if its just a few miles, taking it sort of easy. My long ride comes on Sunday morning when I'm out the door at 7am, and do a 40 miler. Thats about all the riding I can fit in as my kids playing baseball, family stuff, etc.

Its a lot easier as my kids have gotten older. When they were youmg I didnt ride much at all.

Another thing you can do when you cant get out on the bike is regular calisthenics. Knee bends/squats with weights really builds the quads for when you hit the road.