I completely sympathise. I actually love my MIL and FIL very much but I would go crazy if they announced they wanted to move near to me.
My view (shared by others) is that the chat you need to have is with your DH. You need a proper sit down chat during which you discuss how you see your lives going, ie what your long term plan is with elderly relatives etc. You need to be honest with him, i.e. you need to say:
(1) I like your Mum very much (best to lie here) but my priority is (a) our kids (b) other older relatives nearby
(2) Your Mum doesn't drive and I really do not and cannot spare the time to ferry her around/look after her
(3) I'm sorry if that makes me sound bad, but I'm being honest and it's better to say it now than let her down when she's actually moved
(4) If she does decide to move near to us (which after all, no one can stop) we will have to set ground rules. This means (and then set out your list). I will stick to these rules at all times, because I need them for my own sanity. I have needs too and one of them is having some time off/peace in my own home
(5) We need to have this ground rules chat with your Mum before she makes any life-changing decisions.
Hope this helps. You have my sympathy, and I agree that ultimately it is DH's issue and not yours. If he doesn't want to do what you suggest he will have to be responsible for his own Mum...