I don't think you're following my question.

If you bid and have a contract, then how can you quit? Aren't you bound to complete the job like the electrician in your example?

If you do have some kind of clause that does allow you to quit mid-project, then why can't you use that to renegotiate your rate? "I'm sorry, I'm going to have to quit per this clause in our contract. I won't have to if we can negotiate a contract with a little more elasticity to cover travel expenses."

Obviously, it's not quite that blunt, but the idea is: I can quit and you're SOL or we can change our agreement and I won't have to quit.

<---Former user of the "BigLar Procedure"