Will this work?

I have a pfsense firewall running at my office. It provides dhcp and handles all of the local routing and provides WiFi via an access point. I have no traditional router

At another location hundreds of miles away, there is a router for which I have no admin access. I want to configure a spare router I have and put it at that location to provide a WiFi access point. I’d likely install openWRT on it. That router would presumably be set up as a repeater router connected via WiFi to the original/main router at that location

I understand zerotier can run on the router with openWRT. I would like to establish a VPN from the repeater router to the pfsense firewall 100’s of miles away. The goal is so that I can remotely (from my office) access something like a NAS located on the network handled by the repeater router. There can’t be any port forwarding from the primary router at the remote location but with zerotier basically P2P, i think this would work?