Okay, I think I have sorted this out.
I fully intended to start biking yesterday, but my purpose for leaving the house was to buy two 4'x4'x1/2" particle boards. I was all set to go, but then C. reminded me that it would be quite difficult to get that home. It turns out I couldn't even fit them in the Saturn, either, and Menards "couldn't" cut them down for me (I really needed 3'x3', but they don't sell those). Stupid Menards. Really? A lumberyard can't cut through 1/2 an inch of particle board? E. and I did end up biking to the archery range afterward (at 9 p.m.) (and it was still light out!) (which is a rant for another day) because we have this nifty carrying case that I can strap around my body.
So to keep this simple--I will make every effort to bike when leaving the house, but I will use the car without guilt when:
1) Traveling more than 5 miles with children
2) Inclement weather arises, although if I am alone I should make every effort to bike if my safety is not at risk, and
3) Transporting anything larger than will fit in the bike trailer and baskets.
Did you know there are a lot of blogs about bicycling? I am learning a lot in 24 hours. Fascinating.