I don't know what you have now as your office router, but if it is not pfSense already, then I would replace it with pfSense. Then you have 1 router that can do it all easily.
If you put a separate pfSense router in your office LAN somewhere, then you will have to add static route/s to your office router telling it about the pfSense and what subnets are reached through that.
Also, I would change 192.168.0.0/24 at home to some other less popular private subnet - e.g. use something in 10.0.0.0/8. That will avoid pain when you take your laptop to a cafe that uses 192.168.0.0/24 and try to VPN back home.