GoalTo have a secondary WiFi network for guests, on a separate radio, in a separate location from the main router.
HindrancesI have a single CAT5 run to the opposite side of the house, plugged into a media center. Using a switch to run both the AP and the HTPC seems like a waste. I'm also not a pro at static routing, so simple is better.
Hardware neededAll I used was a DD-WRT capable router and couple net cables.
SetupSetting up the separate DHCP server was pretty easy following their wiki article.
Extra RecommendationsAfter setting it up, it makes sense to ensure the address the new LAN uses to reach the main gateway has heavy QoS to prevent guests from overwhelming LAN requests. If you need services to be reachable from both Wifi APs, such as remote controls on phones, simply create a public port that only the internal addresses can utilize. An example is forwarding port 8080 to my HTPC, but only allowing source addresses from inside my two LANs to utilize it.
TCP [source]192.168.1.0/24 8080 [destination]192.168.1.50Don't forget to turn on AP isolation so guests cannot access one another.