i install setups like these all the time. i have had really good luck with bufalo tech equitment. it is compariable to linksys but a little nicer. the prices are around the same. the cool thing is, the buffalo's have access points with built in switchs. they also can have external directional antanas attached to them. what i usually do is run the access pint in the house and then run the antena on the roof and link up with the remote access point. the two access point can be switched on the fly from point to point and access points. this way the only communication from the access point will be with the other access point. then all you buddy has to do is plug his machine directly into the access point at the other end.

the set up is pretty easy.