[ADTech]

So something like the sky 60 antenna with a pre-amp would not do the trick?

Goodness no, I would be embarrassed to call that thing a long range antenna. There isn't much to it beyond the hype.

Use the interactive maps feature to place a marker on top of the hill that you have access to and generate a new plot. That will provide an estimate of what signals might be available up there. I will operate under the assumption that you will be able to provide a clear signal path back towards Portland.

If we were to do it ourselves, where would we start?

Obtaining the use of the spot on top the hill should it belong to someone else. Clearing trees, if needed, to allow the signal to get to the antenna.

Would the antenna itself need power, and would amps be needed somewhere on the 300 yard coax run?

Yes, you'd need amplification. You'd have to balance the cost of ultra-low loss transmission line (3/4" coax hardline, for example, as the extreme) with possible successive stages of amplification needed for transmission lines with higher losses. You'd also need to provide for operating power for the amp(s) which could be its own set of issues since the simple versions typically used with consumer preamps wouldn't work that far away. Add in some tilt compensation due to higher line loss at higher frequencies.

Are there companies out there that would install such a system 300 yards away

You'd likely find the pot of gold at the end of the rainbow first. You'd probably need it to pay for the system.