OlyComputers 110 Practically a Master Poster

I'm putting a network infrastructure in at my families home. Most of the buildings that need to be connected are within about 300 feet of the central structure where the patch panel is installed, but I need to run one cable to a cabin that's roughly 700 feet away. This is 700' through the woods, so putting two switches in the middle isn't possible.

I know that you can use the netowork-over-power standard which is rated for 1000', but I've never worked with it before and don't know if I'd trust the connection speed.

Here are the three questions that I have:
1. Is running network over power lines really viable at a distance like this?
2. Is there a way to amplify the ethernet signal without a full switch/router/hub? I could run power in the conduit to power an amplifier, but i couldn't put something as large as a switch at 2-3 points along the run.
3. Is there any other networking standard that would be effective at this distance, I'd be willing to do coax or network-over-phone line if I had to, but I'd really like to maintain full 100mbps speed (not so optimistic about gigabit)

Does anybody have any ideas?