Justsmith, its you that decides where they go, you must be firm and selective and it has to work for both parties completely. Be fair and firm you cant have issues where you cant have access at certain times. B+ is bang on the mark farms are your best bet.
i have 12 apiaries now, when i first started i almost begged people, then i soon found out you dont have to do that, most give you land to use as their generally good educated people who care about the environment !! last week i had a lady ring me up out of the blue offering me a place on a Manoir, with over 20 lime trees, Mmmmmm didn't think about it for Long. Smashing apiary going in next week.
In the long term, the work you do now will pay off dividends in the future. no hassle and go there when you want. be honest to them and yourself!!
Use google earth, maps etc. one has a ruler setting so you can measure between apiaries or roads or distance form and too other beekeepers or houses. all really helpful.
Best of luck