PFsense not working with second subnet

Because the external interface on R2 is on the same LAN as the clients on 192.168.1.0/24, you'd need a route on each client on 192.168.1.0/24 to route to 192.168.2.0/24 via 192.168.1.2. That should do the trick (assuming R2 is routing, not NAT, and has no firewall.)

If I were you, I'd throw the link between the two routers into its own administrative VLAN and then you could route through this VLAN.

To summarize the comments -

Your clients on the 192.168.1.0/24 network are unable to reach the Internet or ISP router (192.168.2.1) because that router does not have an explicit route to the 192.168.1.0/24 network through the RRAS server (192.168.2.100).

Possible solutions:

• Add a static route on the 192.168.2.1 router from the 192.168.1.0/24 network through a gateway of 192.168.2.100.
• Combine the two separate subnets so they are on the 192.168.1.0/24 (or /23) network, which is local to that ISP router.
• Have the RRAS server perform NAT on the connections so that the ISP router will see the connections as coming from 192.168.2.100 instead of the actual source.