The point of the strong towns movement is to reduce suburban living (particularly when people commute into town for work), which is the worst of both worlds. If anything it should make life easier for people who actually work in rural areas rather than using them as a fancy dormitory.
The suburbs by their very nature take more than they give from most services - roads, water, you name it - and push up land prices and tax rates. They don't tend to offer much of what rural neighbours would need - the people who live their are car commuters, so they go to the bank/doctor/etc. in the town/city where they work, and they do their shopping at the big box store on the highway. Self-sustaining small towns - the kind that can support a population that lives and works in the area - are very much in line with the strong downs ethos, and those are the kind of towns that would benefit their rural neighbours too.
The suburbs are next to the city, not "many hours" from it. It makes no difference to rural communities if they are there are not, they just go to the city instead, at minimal extra travel time.
