Down the Garden Path

I sat down with Coleman's book last night. It's about market gardening, but at some point, the difference between "ordinary" vegetable gardening and organic, sustainable market vegetable gardening is pretty subtle. He offers suggestions for the size of rows: 42" or 60" of vegetables. I went for 42" - although that garden soil looks fluffy and comfortable, I have no desire to have to lean on it to reach the middle of the plot. (There lurk nettles and goatheads and stickers, not to mention the cutest little milipedes known to man.) Unfortunately, he recommends paths designed for your walking tractor (preferably Italian, and blue). Nothing for the person who doesn't have a walking tractor. Bizarrely, this seems to be a topic neglected by those other OCD gardeners out there. 12"? 18"? 24"? How to combine the most comfortable space with as much growing ground as possible?
The math works out nicely in a 25'x25' plot with 42" rows and 18" paths, so I guess I'll plan for that for now.