This is a doable project, but...
You ain't gonna do it alone.
The other people on this project are going to be the kind of people who give you a blank stare if you ask them if they caught "Friends" on TV last night. "Never heard of it. Is it new?"
Mathematics rears its ugly head...
ZYTRAX - Wireless Calculators
See:
Power Budget - total power of your system in dBm.
Free Space Loss - power loss over distance.
System Performance - How far will it go, will it get there or what is my Operating Margin?
Fresnel Zones - How much more than LOS or how high should my antenna be?
If you know any ham radio types, buy them a brew and have a sit-down.
'nother link:
Radio theory and link planning for Wireless LAN (WLAN)
Bring money.
Read the last post in this thread:
http://www.wirelessforums.org/wirele...ible-4824.html
Depending on what you do for a living, this is the kind of thing that looks good on a resume.