I have had this Lionel Dealer for a number of year but don't have any idea of it's value. I don't see any on ebay or other reference sites, thought y'all might be able to give me an idea. I have enough 0-27 track and accessories to fully populate it, does that help its value if I were to sell it?
My suggestion: try to sell it locally on Craigslist for $175, track included but not attached. If someone offers less, you can counter-offer without the track as a bargaining point. Local delivery negotiable too. It's obviously not practical to ship economically. I've had pretty good results selling on Craigslist but I instruct responders to give a phone number for a call-back because email inquiries are often phishers/spammers. Post your ad with good photos for best results. You can always drop the price if necessary. Might sell better closer to Christmas time.
If you want to try for more money, install the track and get a basic train-set train and transformer to go with it, take pics of the whole thing set up, and you can demonstrate it in operation to get people interested. If they offer less, deduct the train from the offer...
I don't claim to be an expert on valuation; this is just my gut feeling of what I would do.