If you're planning to use your tractor in between the rows, you may want to use a bed system for your garden. With the bed system you'll till 4'-5' wide rows and leave an untilled 4'-5' path between the tilled rows. In the tilled rows, depending upon what you are planting, you either plant across the row or along the row. You might plant your lettuce across the row so that you have lots of 4' long rows of lettuce. For your tomatoes and peppers plant them two across, the length of the row.

With the bed system you only have to weed the areas directly adjacent to your plants and you also have a good firm path to walk on even when the ground is wet.

Another thing you may want to do is to take a look at companion planting, things like marigolds next to your tomatoes, to reduce pest pressures in the garden.