Hey, Russ; welcome aboard. I'm not a live steam expert myself (I have my first one on order), but I do buy and sell quite a bit on eBay.
You'd probably get a higher price on eBay, simply because most of the members here are in Europe, and the cost of postage will likely depress their bid, and, very few model US style, which the Ruby is. You might also try to find if there are any live steamer clubs in your area. I'm thinking seeing it first hand would generate more interest.
The Ruby is at the low end of the spectrum for live steamers, so temper your expectations accordingly. A new one is only around $500. Look at the "sold" listings on eBay to gauge its value - looks like the sell for $300-$400 used.
The title should simply be "Accucraft Ruby Live Steam Locomotive" or something similar. Make sure you spell it correctly - folks won't find it in a search if you misspell it. You'd be surprised how often that happens. Some people deliberately search for commonly misspelled terms to try to get a deal.
I would start it at the minimum price you are willing to accept - I hate auctions with reserves and won't bid on them- and set a buy it now at the amount you'd like to get for it.
Time the auction to end on Saturday or Sunday - more bidders on line those days. Don't use an overly long duration - 7 days is about right. If you go longer, it won't get you more money; most bidders wait until the last hour or two to bid. Seven days gives interested parties plenty of time to notice it and to think about it.
Be candid in your description, including your reluctance to steam it up and why. You might even mention it's for s good cause (I just finished putting two daughters thru college, so I feel your pain). Be sure to provide lots of photos from all directions.
Watch your email closely and respond quickly to questions bidders might have. I hate it when I ask a question and it goes unanswered.
Well that's about it. If I think of anything else, I'll let you know. Good luck.
"It is one of the happiest characteristics
of this glorious country that official utterances are invariably
regarded as unanswerable."
-Sir Joseph Porter, First Lord of the Admiralty (HMS Pinafore)