You must live in my neighborhood! :)
You bring up two important issues: a. Power at the remote site 800 feet away, and, b. The Fresnel zone of a pole only six feet tall
You can look up the Fresnel zone stuff separately, which, in my experience, is more theoretical than practical since you just shove more directional beam power to overcome the losses due to lack of height.
Power is an issue.
I'll ping "alt.internet.wireless" & "sci.electronics.repair" with this post, who may be able to assist you more so than I can in how to set up the power (be advised to ignore the three infants on s.e.r if they respond).
What we do here in the Santa Cruz mountains, where the zoning is 40 acres per household, is "bucket routers" which are simply routers plugged into anything we can plug them into, between homes when we need to clear obstructions to our Line of Sight (LOS) WiFi transceivers.
But your suggestion of solar seems far better than bucket routers.