The question is, will there be cell phone service where you are camping? If so, chances are you can use a cellular modem to connect with.

Check with Verizon Wireless, they have an EVDO modem that slides into the PCMCIA slot of your laptop and will give decent speeds if you are in an EVDO coverage area.

Alternatively, Cingular and T-mobile also have GPRS/EDGE modems that are slightly slower.

Both providers should have a 14 day trial where you can try the service and modem and return it if you aren't satisfied.

If you have a Blackberry with either provider, you can tether your Blackberry to your laptop with a USB cable and use that as a modem.