How unreasonable would it be to setup a small LAN within an existing LAN? I'm setting up a series of video surveillance servers and a number of IP cameras in a client's location and cannot have my equipment on the same network as their local machines. My network is essentially self-contained and the only device that anyone needs to access is a web-app on one of the machines.

Basically I'm thinking of installing a SOHO router which would uplink to their LAN, and then set up some NAT rules on both their router and my router, to allow outside access to the webserver.

Is there anything fundamental that i'm missing which would prevent this from working?