I haven't used a tiller but want to encourage you to think about hand digging your garden- I know it sounds awful but:
-you can do it with children present (Eli loved helping last summer- throwing rocks, playing in the dirt, using his bulldozer in the bed, etc. Where as a tiller is loud and dangerous and kids should be far away.
-it is better for the soil- it maintains the strata of the soil, doesn't involve petroleum products, etc.
-its easier to remove rocks etc. by hand than with a tiller.
-its good exercise
-narrow raised beds are easy to double dig and look fantastic when planted
-it is a quieter more peaceful approach to gardening
-and it isn't much harder than using a tiller.
I dug 8 beds by hand last summer with Eli and we had a blast. They look terrific and I have great pride in them. I'm not condemning the use of a tiller, just giving you another option to think about.
Good luck with your garden,
Ps. to double dig- dig down one shovels length, remove dirt from a 2ftX2ft area. Use a pitchfork to loosen soil beneath. Move to next area, transferring dirt to the are you've already pitchforked. It sounds hard but you get the hang of it quick!