I saw one in DC recently. 1960
Ambassador. Looked legit, but the price was a little low. $4400. I initially flagged it for spam, then realized I might have it wrong, but since i still had the ad up, I emailed the person.
They sent back a bunch of great pics, mostly original. I asked when I could come see it. Then they said "I'll walk you through the process", and included the mess about Google wallet.
Here were the tells:
If the person provides an email address and doesn't use the Craigslist hidden email, it's probably a scam.
If the email address is hotmail, it's probably a scam.
If they have an email address on the listing, but then give you another email address to reply to, almost certainly scam (she went from a hotmail to a gmail address)
Anything involving the person not being able to walk you through the purchase or let you see the trailer before giving your personal info is an automatic red flag.
Anything weird like Google Wallet or PayPal (though PayPal can help facilitate a legitimate purchase in some ways)
and... if it's too good to be true, it probably is.