OT: setting up public wifi

I need to set up wifi in a church, and share the wifi with the rectory (a separate building). I've been doing some research, but am looking advice to help me get through this quicker.

Here's what I'm thinking about so far:

1) Get a router that has a "guest" account, or some other internet-only connection mode. The church offices will be using the same network, so I want to keep the general public from doing things like accessing file shares, using printers, etc. I probably want one with dual antennas, and at least one must be detachable so I can hook up an outdoor antenna (see #2, below).

2) Use an outdoor antenna to send signal to the rectory. I'm not sure of the exact distance yet (because I'm not sure where it will be possible to mount the antenna), but it should be no more than 150 feet. Here's a link to the antenna I've been thinking about: http://www.newegg.com/Product/Product.aspx?Item=N82E16833995096

3) If signal in the rectory is weak, use a range extender in the rectory, possibly with an outdoor antenna. The rectory is small and won't need more than a single access point.

4) In the church I will need to use either range extenders or multiple access points. Maximum bandwidth is not as high a priority as being able to handle many users. So I'm not sure if it makes sense to go with the 802.11n 150 mbps or 300 mbps. And I'm not sure if I should go the easy route and use range extenders or if I should hard wire multiple access points to the router.

Here are some of the range extenders and access points I've been looking at:

http://www.newegg.com/Product/Product.aspx?Item=N82E16833704192
http://www.newegg.com/Product/Product.aspx?Item=N82E16833704187
http://www.newegg.com/Product/Product.aspx?Item=N82E16833704048
http://www.newegg.com/Product/Product.aspx?Item=9SIA24G1732603

5) The church has concrete floors and outside walls. An addition was recently built, and a couple of the old concrete outside walls are now inside walls. The rest of the inside walls are sheetrock. The addition has drop ceiling tiles, so I can run some wires up there. That won't be possible in the old part of the church. The rectory is wood frame construction with vinyl siding over plywood, and sheetrock interior walls.

I'd appreciate any advice you guys can give.

-Rob