Expanding my network to the horse barn to connect a video camera

Can you wire one of the satellites (AP) via solid copper core, UTP, CAT-6 cable? You could run the cabling inside a pvc pipe or something similar to protect it from the the elements. Terminate the CAT-6 cable with a punch down keystone jack and the run an ethernet cable from the wall jack to the satellite. That would give you wireless access in that area if the satellites have ethernet ports.

I could certainly run Cat6 cable but I am trying to stay away from that solution as I have concrete slabs at both ends that would be a real pain to work around.  In addition, the barn is made of 1" plywood clad on both sides with galvalume. I could get through that pretty easily but the concrete would be a pain.  In addition I have water, sewer, electric and wires for my electric fence running through all of this so I'd have to be real careful I didn't cut something!

Window access maybe? Conduit below ground to the concrete slabs, then up and over the concrete, up a wall to a window (and get creative) then down and inside. Another satellite (AP) wouldn't do you any good because the connection for the backchannel would be WiFi and it sounds like the barn is not very friendly with WiFi signals. 

An aerial approach to a window or door jamb?

I'm familiar with extending cat 6 Ethernet cable so I may have to fall back on that.  I assume that if I didn't do that but could still connect my speed would be significantly slower because the backhaul would be using a different wireless channel as opposed to the CAT6 Ethernet cable.  Is that correct?

However, I've been advised to consider a couple of other ideas, neither which I'm familiar with so I was wondering what you thought of these suggestions:  

TP-Link 2.4GHz N300 Long Range Outdoor CPE for PtP and PtMP Transmission | Point to Point Wireless Bridge | 9dBi, 5km+ | Passive PoE Powered w/ Free PoE Injector | Pharos Control (CPE210)

Not being familiar with this hardware, would i just link it to the primary Deco Node wirelessly?  Would the network name be the same throughout or would I be installing a separate network?  Are their downsides to this solution that I am missing?

One other question - when trying to read up on this CPE, I happened to see this unit:

AC600 Outdoor WiFi Extender, WAVLINK High Power 1000mW Dual Band Access Point | Supports AP/Router/Repeater/WISP Modes | Weatherproof | Ethernet Port | Long Range WiFi Repeater for Backyard, Garage

Would this be the similar to the other idea or better?

Thanks for your help....I really appreciate it!

I don't know if the galvalume covering on the inside and outside of your barn is going to work well for WiFi. It almost sounds like that would make your barn a Faraday Cage, hence my suggestion to hard wire if at all possible. That way, the WiFi signal would work better inside, or, if you had AP's with ethernet ports, you could plug other devices directly into the AP for a wired connection back to the router in your home.

I suppose you can try either one of the products you found and see how well it works.

A well made and designed mesh WiFi system will use a dedicated 5GHz channel for the backhaul, whether it is WiFi or ethernet. I have two satellites on my mesh WiFi system. One is hardwired to the router for the backhaul and one just uses the dedicated channel for the backhaul. Both are fast but the hardwired one seems to be a bit faster and more consistent, but not that it adversely affects performance. Keep in mind that the more devices you have on your WiFi network the slower it may become. That's why for both of my home theater systems I've hardwired them so I don't have to depend on WiFi. That being said, I have about 15-20 devices connected at any one time via WiFi and there are no issues.