Considering Getting a Roommate for Healthy Reasons

I don't know where else to post this, so maybe this is the best forum for it. I'm considering getting a roommate if I can find one who will cook in exchange for a room. We can share the utility expenses and cost of food. My question is, should I have a contract and if so, what rules or stipulations should go into the contract? I'd like an understanding up front about what is and is not allowed.

I haven't had a roommate in decades, but if I could find the right person, I think it could work out. I like to spend all my time outdoors, so the roommate would be responsible for the cooking and cleaning. It's a small house and my bedroom and my laundry would be my responsibility. But the commons areas that we share would be her responsbility, which would be less than 1000 sq ft. I wouldn't expect a home cooked meal everyday; I can eat leftovers, sandwiches and salads. But it would be nice to have someone prepare the stuff (cut up the veggies for the salads, cook stuff in the crockpot or stove, etc). We could freeze individual servings so I could help myself when I get hungry.

How can I make this work? To be honest, bringing someone into my home scares the daylights out of me. I've been alone for a long time and I like it. But I've gotten into the habit of eating out or eating junk food again since I hate to bother with preparing meals. So I've gained back the 40 lbs I lost and I have to get my weight under control. I want to spend all my time working on my gardens and when I'm focused on a project, I don't want to waste time cooking and cleaning.

Anyone have any ideas of what should go in the contract or any suggestions on how to weed out the riff-raff? I really want to find someone I could be compatible with.