The good thing about Dorset is it becomes rural very quickly if you travel about 5 miles in any direction from anywhere. Unless your direction is towards the sea, in which case it becomes wet.
I suppose you'd decide if you want a beach on your patch or not!
Just to be awkward, Poole to Bournemouth is exactly 5 miles - no ruralness (don't think that's a word, but never mind!) at all! But you're not far wrong, you can get to the countryside nice and easily from pretty much anywhere.
I'd just like to add that my patch has one of the best beaches you'll ever find!