Assistance required - Guest Access on new Wireless Network

[manzaboy]

Hi, First post so be gentle!

I am just trying to setup a new wireless network for scratch for a Charity.
They lease their building out so want to provide guest access for visitors to just access the Internet and not the local network.

I was looking at a setup which uses a new ADSL modem router and then gigabit cat 5e out to a gigabit switch which branches off with further cat5e to 2 other routers setup as wireless access points in different parts of the building.

I was trying to avoid multiple SSID's or doubling up on the access points and the ADSL routers I was looking at appear to support Guest Access however I am dubious as to whether this would work through the access points?

The ADSL modem router I was considering was the ASUS DSL-N66U (supports Guest access or multiple SSID's) and then using Buffalo AirStation 1300 as Wireless AP's.
Happy to consider alternative hardware if suggested. The requirements are Dual Band N class with gigabit ports.

Anyone offer any advice on the guest access?