Yes why not ? Do you have an asa or vpn server ? Provide it a WAN address from an ISP simulating router. Now Denver will be connected to ISP. Create the other side same way. All you need a L3 reachability from one site to another. Then you can configure VPN and connect using Denver server.
Watch the Lab #2 and come back and see this one. It will make more sense.
If we wanted to have clients in the remote network (Denver) connect over vpn to your main network, is there a way to simulate that?
Yes why not ? Do you have an asa or vpn server ? Provide it a WAN address from an ISP simulating router. Now Denver will be connected to ISP. Create the other side same way. All you need a L3 reachability from one site to another. Then you can configure VPN and connect using Denver server.