I do stuff similar to this, but instead of having 1 VPN tunnel between the remote box and the pfsense box, instead each client on the LAN has to run openvpn client and connect to the remote box. then all their traffic is routed over the tunnel. this takes pfsense out of the openvpn equation
disadvantage - instead of one tunnel, there are many. more to manage, scalability problems I imagine..
but end goal is the same, clients on LAN all traffic goes through tunnel