I found my Escalade on Craigslist for Jacksonville Florida. They are plentiful down south. I wouldn't look any further north than Kentucky. I like cargurus.com lately, but Auto Trader is also good, and sometimes you can get lucky on craigslist.
-Geoff
Seeing how we're out-of-state, a nice little trick is once you've found one
you really like, contact the local dealership in their state, and have the owner
take the car to his local dealership for a complete pre-sale inspection that you
pay for.
The dealership then emails you the inspection report. Most any legit seller will
simply take their vehicle to a local dealership for an inspection (that you're paying
for). Some may not, and that probably would saved you time & grief.
I myself, prefer to buy government vehicles. They tend to not have any reason not
to be honest & transparent about it. I talked to the Chief about my Tahoe before I
bought it. He was very helpful, filled the gas tank for me, picked me up at the airport, etc.