Unfortunately, Craigslist is particularly bad for scams simply because it's free.
There's no absolute way to spot an scam but there are some signs. Certainly if the price is too good, it's always a red flag (although I'm an eternal optimist so I'll always think that not all great deals are necessarily scams). Very generic ads with few details are also a potential. No contact info is another potential (although not all sellers will list contact info). Same / similar ads in multiple cities are usually a great sign of a scam. Also if you do get some info (e.g. VIN), on it (from the ad or from a response), google it - so many times, I see great deals on Craigslist and eBay only to search and find the same vehicle behind sold by a dealer somewhere (scammer just used pictures / info from the vehicle that's really being sold). I think anytime it's a great deal and the seller will ship at his cost (especially something like a motor home), it's a scam. Stories like being transferred overseas for work or military are usually scams. etc.
Here's the one I noticed (also appeared in another 6 dozen cities but Craigslist already yanked those). All 2003 Providence 39s, all around $36k, all appear to be pictures of same mh).
39S 2003 Fleetwood Providence - $36500 (cedar rapids)
This RV is pretty easy to drive. Only a regular driver's license is required to drive this coach. There are 2 roof AC units that both work. The engine or dash AC also seems to works, although it is cold outside This is a nice coach at approx 39 foot.This RV was just driven several hundred miles with no trouble The 7.2 liter Caterpillar 330hp TURBO DIESEL engine runs great, no problems.The 6 speed Allison automatic overdrive transmission shifts great also, no problems.
posted here (links will probably be flagged in near future):
39S 2003 Fleetwood Providence
Fleetwood Providence 2003 39s
Providence 39S 2003 Fleetwood
39S 2003 Fleetwood Providence