If it was me I would purchase two gl inet routers. Their super easy gui can setup VPN servers and Tailscale. Can also use Luci for Openrouter. All my routers are this brand. I use them for Tailscale but I know the VPN server exists for both OPENVPN and wireguard. Very plug and play and if they installed Tailscale they could easily troubleshoot out of state as long as there’s power and internet