>why would you need one?
Contracts are most useful for sorting out misunderstandings. If you say, you'll tear off the siding and remove the bees and you do that and the homeowner comes back and says you promised to put it back on, you need to be able to support what it is you agreed on. Anyone can still try to sue you if they insist, but with it in writing they probably won't and if they do you have a leg to stand on.
I understand in your situation where things can go wrong in a hurry, but I probably misunderstood the original question. I was just thinking if I was the landowner and you wanted to put bees on my property, i'd be wary of a contract. Just me.
But be careful since if there is a question of interpretation, contracts may be construed against the drafter, so careful with the wording!