As much as it nice to think he needs to choose the job he wants, it's also your life and that of your child his decision affects. So I think you SHOULD have a say. You say you think he'll choose the one by his parents because he thinks that's what you want, but it sounds to me like it isn't what you want. You need to tell him so. Maybe it's not the job he wants, but he thinks you want him to take that job. You just need to tell him everything you wrote here.
Sure, living in the city, it's more expensive, but if moving to a smaller town will limit the two of you going to school and it's one of your goals, then you need to take that into consideration. With an education, you can always move up and make more money and get the bigger yard or bigger house down the road. I grew up in small-town Utah and I can tell you that as a kid, there were very little things to do and that makes it so much easier to get into trouble.
My suggestion is the two of you need to sit down a make a list of the pros and cons of each move and each job and then decide from there. Good luck.