@spickles I would think the easiest way to replace a Cisco ASA 5505 would be use pfsense as a firewall not a router. Keep using your Cisco L3 switch. I do that at my home. I use an Cisco L3 switch and route between my L3 switch and pfsense. You lose pfsense control over your local network. This would not be an issue with you as you will already have that with your L3 switch. Setup pfsense with no vlans and keep all the vlans on your L3 switch. Then set up your firewall rules and static routes to your L3 switch.