I typically don’t have much to offer due to the fact that most of you do installs worth more then the houses I work in however in this situation I could offer some tips.

Mesh networking with dedicated backhaul radio can work, the key is to make sure the backhaul capacity is as good as the demand on the “ap”. Choosing a mesh kit without dedicated backhaul is pointless given the demand that the homeowner is going to put on the system.

The more devices connected increases the “ap’s” required, this would be where your more expensive 3x3 Mimo etc radios shine as they can reduce the load on the “ap” requiring less given that you can still maintain coverage on your building size.

Now for what’s causing the real headache, cabling. Unless the client is aware of wifi that runs on batteries some cabling will be required. Obviously one needs to be hardwired, keep your wireless backhaul hops to one. Meaning don’t have the first one hardwired and then the third hopping to the second and the second hopping to the first.

I have never tried this but maybe some of the others have, would using Ethernet over powerline work for connecting the ap’s back to the router? If it would maybe this would open more options for ap placement. 3 stories and 6500 square feet has a few different possibilities for house shape etc so I can’t even comment on how many “ap’s” your going to need.

I worked as a Technical Assistant to the CEO of a wireless internet provider for a few years and following these principles avoids trouble.