Your best chance of getting something installed is to contact one of the major DCC suppliers who do decoder and sound system installations in the smaller scales and ask if they can install the AirWire900 for you.
I use AirWire900 and battery power exclusively, except for a Mimi live steamer, and have been very happy with it in my Bachmann Spectrum 1:20 steamers -- a Shay, a Mogul, and two Consolidations. The nicest part of wireless, battery-powered DCC is that you never ever have to clean track. In my case, I chose the AirWire900 because my track plan had too many reverse loops and turnaround wyes for track power, plus the fact that trying to dig into Arizona dirt is like trying to dig into a rock.
At least one DCC supplier that I know of who supports G-scale and can possibly install your AirWire is Bruce Petrarca at Litchfield Station in Munds Park, Arizona. His web site is http://www.litchfieldstation.com
I am looking for a preassembled R/C & DCC powered locomotive. I have just finished laying out my garden railroad tracks and want to use battery powert. I am by no means an electrical engineer and do not feel comfortable taking my LGB engines apart. Do any advertisers in Garden Railways sell engines ready to run ? I prefer the Airwire 900 set up or one similar.
Thanks to all for the good reading and assistance.
PJ
Get the Garden Railways newsletter delivered to your inbox twice a month