Need to expand current network across an open field

Trying to find a solution to a more unique problem.... Friends of mine have a property inside the city limits, but have quite a large property. Because of their location they have no cable, and their old phone lines can't handle DSL. They have satellite internet at the moment.

Now the issue is the main house has this connection, but they have a smaller house about 100 feet across a field. Their daughter is moving back into this other house with her family and needs internet. Rather than get a secondary satellite connection, I thought they could use wireless.

The way I have currently set them up is with an Airport Extreme Base Station, with several Express 'repeaters.' What I thought would work is to have two directional antennas - one at each house - to beam the connection across. The smaller house could then have it's own wireless network.

I'm fairly knowledgeable with networks, but I have zero experience with these types of antennas and this set-up. This second network would have another router and thus complicate things - would Bonjour discovery work in this instance, or will the additional router hide the other network?

If this wouldn't work, the other option would be to run Ethernet, but that would require a bunch of digging and wiring which I'm hoping to avoid.

Anyone have experience and can recommend brands too?

 

Thanks for the links....