We are starting to look at 5th wheels and motor-homes. From a potential buyer perspective (not right now, sometime in the future - sorry) I can tell you where I look and what interests me. Of course other people will have different options and preferences.
1. I look at RV trader, autotrader, dealer sites and simlar places, but mostly to get pricing and see what is out there. I figure the dealer prices there are 30% over what the sale price should be in a private party sale, both because the dealer will negotiate the asking price and because with a private party you expect to pay less because you do not get perks like detailing, inspection etc and because you have a less viable seller if there is a problem. A dealer might work something out or do some repairs if they sell you a lemon, a private seller - no way. So you expect a lower price from a private seller, plus they do not have overhead to cover. If it is a dealer I might go look at it just to learn even though we are not buying right now. With a private party sale, I would not do that. I would not even contact them with questions unless we were really excited about the RV. I do not want to bother an individual or get them excited. Thus, if you are getting no contact whatsoever it does not mean people are not looking at your ad. From my perspective, the more detail the seller includes the more interested I am. I am especially interested in upgrades and add ons as I see that as one of the advantages over buying new. Did you add solar? Three extra batteries? Lego blocks for leveling?
2. I look on craigslist, E-bay, and Facebook, and especially RV forums to see what private sellers are offering. Sites like RV trader seem to be nearly all dealers even when they say they are not dealers. There are two reasons private party sale is appealing to me: a. I do not want to pay the dealer mark up. I can clean the RV myself as long as it is reasonably clean and maintained to begin with, and I will have it professionally inspected before I buy one from anywhere. b. All of our camping stuff is old worn and tent camping oriented. I like the idea of finding an RV already fitted out with some of the essentials (folding chairs and tables, specialty tools, fun stuff.). It saves a little money and a lot of figuring out what you need and then shopping. The dealers remove everything from the RV that is too bad. Eventually I will probably replace most of that stuff, but it would be nice to not have to track it down and buy it at first.
3. Craigslist is mostly scams, so I am cautious about contacting anyone through CL. I would focus more on Facebook, E-bay and forum for sale sections.
4. Although we are still considering both MH and 5th wheel, the floor plan is critical to us and I think to most people, thus you will have to wait until someone looking for your particular set up comes along. Some people want or need bunks for kids or guests, others want living space for just two people and do not want to waste any of it on guest space. Some want two doors, propane fridge, electric fridge, solar chargers, etc. I think most people are going to be looking for something very specific.
5. If I see an Rv for sale in front of a house that looks appealing and I was ready to buy one, I would stop and look. To me that is where I perceive I will find a better bargain, plus I know it is not a dealer or flipper, not a scam, I can see at least its exterior condition before I bother talking to/meeting with the owner, I can see if they have a place to store it indoors so I have a better idea whether they are lying when they say it was always stored indoors (everyone says that, I saw one with a for sale sign at an outdoor storage place near me and later saw it advertised on CL. Ad said "Always stored indoors" I saw it sitting in the storage yard all winter.).
6. When we buy a "practice" Rv in a year or three, we will be looking for a bargain and it is most likely we will find one somewhere with a for sale sign on it. Frankly we will not be all that picky, mostly looking for something we can clean a bit and it is ready to go. However we will not tough anything with any sign of ever having had a water leak or any soft spots - wouldn't take it for free. When we buy our retirement home RV, it will be very specific. We will buy if from whomever has it, possibly even a dealer if we cannot find what we want from a private sale. In that case, a few thousand dollars difference will not matter as much as getting exactly what we want.
7. Hunting for private sales, I find a lot of people start out way over priced. They see dealer asking prices and think that should get that or close to it, or more. Everyone thinks their particular RV is better. I also see some RVs where the pictures show they are filthy or worse yet water damaged. I do not care if it is detailed spotless - that usually means you are actually a dealer or flipper. However a Filthy RV is not very appealing. It reflects owners who probably did not bother with maintenance.
8. Having complete maintenance records is a big plus. Especially roof maintenance. My biggest concern is water damage/mold. Mechanical/electrical I can fix.
9. I have found real private party sales are very hard to locate. I think most used RVs that are not really old are trade ins. I suggest you put "Private Party Sale" in big bold letters on your ad.
10. If you include things, the RV has more appeal. For example, if someone included Kayaks or bicycles we might be more likely to jump on an RV for sale. The seperate value of such things is usually pretty small. You can always knock off a few hundred as a credit to exclude them if the buyer does not want them, but an all in package has a lot of appeal to us. The more things we would have to buy that are included the better (MH towing set up, 5th wheel hitch, bike rack, etc.) Not sure about others.