I would suggest not to limit yourself to only looking at "local" cars. That will expand your knowledge as to what is available and how to compare for a deal that you can live with. Take your time and avoid impulse purchasing so you are less likely to settle for something you will wish you hadn't accepted down the road. It is not uncommon for someone to budget for making an out of state purchase for a 'Vette and that is just part of the price of the vehicle. If you look at it like this, you could pay $1000 less for something that you need to fly or take a bus to go pick up. Then enjoy the drive home in something you really wanted. Or you can settle for something local, because it is convenient, and then chase it with mods to get to something you really wanted to begin with. If you search nationally for what you want, you can usually get a forum member local to take a look at it for you. Just hope they are not also looking for a new 'Vette. LoL When I was looking for mine I was infatuated with Night Race Blue, which limited me to '13 and being my second 'Vette I wanted this one to be a GS. I found one in GA with 23k miles, so I bought it and had it shipped to CA, sight unseen. Some people would think I was crazy for buying a car I had never seen before, but with leap of faith and a little patience I got exactly what I wanted.

Looks like you got all the major nation wide search engines. You can also look at the C6 Corvettes For Sale section here on the forums and make a WTB thread. The more detailed in what you are looking for, there will usually be a couple people there flooding the thread with listings they find that match, or are close to what you are wanting. Most of which you will have already seen on Autotrader and Autotempest, but occasionally they will point you towards something that may have slipped past you. When using those national search engines, do not put a max distance, just sort by distance and they will show "convenient" cars first, but will not be limited to "local" cars. This will give you an idea of what you are looking for is listing for to make sure you are not getting hosed when you finally find something you are interested in. I would also echo the suggestion on getting a pre-purchase inspection if you are going a great distance to buy. There are companies who will do this for you at a cost of about $100-200 depending on location. The closer to a major metropolitan area, the lower the price as most charge a per-mile fee on how far they have to drive to inspect the vehicle. They will kick the tires, do a test drive, and take lots of pictures to go along with a detailed inspection report on their opinion of the car and it's potential appraised value. This is helpful in also judging if the vehicle is worth the asking price. Another option is, depending on how active the area you live in, the regional forums sometimes have local events and gatherings of 'Vette owners. Take a drive over there and pick their brains and get to know the locals. This could lead you to a possible local sale that is word-of-mouth and not to be found on any search engines.