At a camp in Alabama (at a university), our group leader had brought a laptop, but could not find a way to connect to the internet. In a previous trip, I had left my Linksys Powerline adaptors in my bag. So I found the switch in the building, plugged in one brick, then plugged in the other brick in our room. Voila, internet. Perhaps if you can figure out a similar way to do this with Powerline, you can get yourself some unblocked ports.