I setup Pi Hole with tailscale on an inexpensive cloud server. It is configured to serve DNS requests over the tailscale interface. Also added tailscale IP address of the Pi Hole to tailscale DNS override to ensure that all devices on the tailnet use it without any additional reconfiguration. For redundancy, I have multiple DNS servers on my tailnet. Family and friends can use it without worrying about portability and be protected at all times, especially on cell networks.