Remote Desktop and WiFi

A colleague just called for help from a trade show. He's running a Remote
Desktop session from a laptop, attempting to control a PC-based robot over a
802.11g ad-hoc net. This setup works well here in the office, but at a small
trade show there are something like two dozen (or more) WiFi nodes, all
manner of b and g and the usual 2.4 GHz clutter and RFI from various
sources. The RD session is failing more than it is working, most likely
because the RF spectrum is saturated. I had the same thing happen in
December at a much larger show, where Netstumbler saw something like 40
computers/APs. I need a solution.

My first thought is to use 802.11a instead, and finding some clear air at 5
GHz.

I've located a handful of USB NICs that do both a and g, and a few that do
a, b, g. I'm thinking about ordering a pair of TrendNet TEW-509UB adapters,
for $25 on amazon.

Are there better solutions for noisy WiFi environments? I don't need a mile
of range, 50 feet is fine. USB is required.

Help!

-John O