If you pull wire to solve the problem, I also suggest underground as the easiest, most economical means.
However, I would suggest you try a vibrating plow, rather than a Ditch Witch trencher.
The vibrating plow will leave a nearly invisible mark, no soil surcharge to dispose of, and move very quickly through most soil types. Usually used for pulling irrigation lines without damaging the surface. Since you can get direct-burial cable, you won't need conduit & fittings.
Give 'er a try...and Good Luck.
PS...don't forget to consider the possibility of interference or eavesdropping on any wireless setup. It's still, at heart, a basic radio station that someone else can tune to, if they choose.