One thought I had was for him to place a wireless access point on the outside of the trailer and have it wired to the laptop. I do not know if this would work though.
He just needs a PMCIA NIC that supports an external antenna jack like an old Buffalo WLI-CB-G54S. Then hook it up to a Cantenna directional antenna 15 feet away, http://www.cantenna.com/ or another kind of antenna.
