@lesserbloops no problem, glad you got it sorted.
It for sure is not a "optimal" sort of setup.. While I am not sure on whatever constraints your having to work with.. And sometimes you just need to get something to work, be it not how it should properly be done ;)
If you have the ability I would look to not having to jump through such a hoop..
Is there anyway for example to connect pfsense to your current routers that are being used as gateways for these 2 networks via transit networks so that pfsense could be used for the firewall router joining these 2 networks together. That way users in network A could just rdp directly to the IP of network B, all you would have to do is allow the traffic you want and in what direction in pfsense.
Optimally you wouldn't need the 3rd router at all, and just connect your 2 different routers via a transit so you could correctly route between your 2 network.. In a truly optimal setup those 2 routers would already be pfsense ;)
I find that pictures are sometimes worth 10k words, and sometimes descriptions no matter how elegantly worded can be misinterpreted sometimes due to different use of terms or misunderstanding of how a term is being used.. The term gateway comes up a lot around here for example.. Users try and use that to describe the IP they set on pfsense interface ;) that is not a gateway, that is the interface IP.. Stating you set a gateway means to me you did that you put in a gateway address ;)
Also users tend to say they did X when they really did (X+y^2) * Z + Q, etc heheheh.. So a "picture" makes sure everyone is on the same page ;)
Which for example is why I drew up a quick layout of how I was understanding what you were up against, so was sure we were understanding each other.