Hello @rcehlersiv
In general, I recommend running a wire (Ethernet or coaxial cable) to outbuildings. The wireless mesh link Nest WiFi uses only runs over 5GHz, which is fast, but doesn't go very far. It's not always the distance that is the issue, but obstructions, including exterior walls, which may have aluminum siding or even a foil-based vapor barrier. That said, if you absolutely positively simply cannot find a way to run a wire, then I would recommend investing in some directional WiFi gear that is intended for this purpose. It will include directional (high gain) antennas that can be permanently mounted and aimed. Those devices will include Ethernet ports on each end, which effectively makes them a replacement for a "real" Ethernet cable. Once those are in place, then a number of WiFi solutions can be deployed, including Google WiFi (which supports Ethernet-connected access points), or products from other companies that support a similar feature.
