Think of a VLAN as a physical LAN without extra cable.
So what you're saying is exactly right, create lan1 & lan2 using separate physical media or virtualize it. Then add firewall rules for connection, as traffic between separate lan:s need to go through a router.
The benefits of VLAN:s are several, to mention a few:
You don't have to get extra equipment for every lan - a vlan-capable switch can handle multiple lan:s.
You can add clients to a specific vlan in several ways, for instance:
Ports 1-4 on switch are vlan2, ports 5,8 & 12 are vlan3 etc.
Create a vlan based on clients mac-adress
You can have a VLAN with clients in Rome, New York, Berlin whereever