This is my current configuration.  All of my internet traffic flows over 192.168.1.1 and uses our internal DNS servers.  However, I recently added an MPLS circuit direct to one of our customers.  They have a bunch of networks (192.168.3.x, 192.168.4, 10.0.1.x, etc., etc.) that I'd like to be able to talk to.  Currently, I have a small group of users using the pfSense #2, and they simple issue a bunch of "route add customerIP mask customerMask 192.168.1.2" so that they can hit machines at the various customer networks.  This works for a small group, but has some problems... 1) they have to run a script to do the route adds, 2) DNS doesn't work on the customer side, and 3) it doesn't scale at all... too many users to make this work on-going.  Instead of users issuing the route adds, I'd like to just add an interface to the main pfSense box (e.g. opt1), and connect the gateway-MPLS directly to that.  And then issue static routes on the pfSense box to get users to the remote networks (like below) automatically.  It would be great if I could get DNS working (perhaps add a forwarder to my internal DNS server?).  The problem is, I don't know if this is a good solution, or if there is something better/different/more appropriate.  If you have any suggestions, I'd love to hear them.

LAN---pfsense (192.168.1.1) ---gateway --- internet
            |---------------------gateway MPLS (172.x.x.x.) --- customer