podrock's given you some great info plus some great local color. What's left is a bit of nibbling at the edges of the problem...

wi-fi? It's for local coverage, like blanketing a coffee shop. The Internet connection would still have to get to the wifi homebase first. Outside of a dense urban area, nobody gets the net via wifi.

Couple of years ago a buddy living in a remote valley in the Sierras got Internet satellite service. I tried to communicate with him one night using Skype, Internet telephony, and it just wouldn't work. Satellite Internet has serious speed-of-light problems, which destroys the coherency of the packets of digitized voice. Your protagonist won't be talking by voice or video with anyone using a satellite...unless you want to add a little dramatic tension with his frustrations trying to be understood using Internet telephony. In that case, I can tell you at times my friend's voice was slowed down to a whalesong crawl, at other times chattered like Alvin the Chipmunk, and throughout there were dropouts and stutters. Imagine the offspring of Max Headroom and a whale. I'd imagine that first contact with an alien species would sound something like satellite Internet telephony.

This is kind of off the wall, but what if a major Internet trunk ran through the mountains near the cabin, and your protagonist happens to be pirating the connection? This could be a tap on a physical cable, but that's dicey--detection is too easy. But sometimes the signal goes via microwave beam, and then all you have to do is stick an antenna up into its path. Or, perhaps the hero isn't a pirate, but thinks of tapping the signal in extremis. If a tower is nearby, go there and break into the equipment bunker. The bunker would have a rack or two of equipment, and possibly test equipment that could be adapted to send and receive. Look for a USB port on a panel, and plug in the laptop. Some hand-waving like that.

A major Internet trunk means high-bandwidth, and that may change the situation. It would allow the protagonist to send video of the bad guys, for example; maybe not knowing what else to do, he posts the video on YouTube, and it takes a couple of days for anybody to notice. Or they notice and think it's a joke; or take it seriously, but morbidly just watch and don't report it, like mute bystanders at a crime. The video goes viral before the authorities catch on. He gets a following on Twitter, and has tons of friends on FaceBook.

I forget who noted how the dramatic problem has shifted from the routine difficulty of communication to the expection of 24/7 connectivity, but all that speculating about YouTube and Twitter and Facebook highlights how the nature of communication is changing as well. At first the protagonist's isolation is frightening and disorienting, like a Borg cut off from the collective; then, when communications are restored, the entire world rushes in, and his plight becomes the common obsession of a good portion of humanity. And that's not necessarily a good thing, as a billion people jostling for a look contribute their own unique problems to the mix. Maybe frying pan into the fire.

Interesting....