I don't think this is a bad place to try and sell your truck, but it shouldn't be the only place. Here, you are reaching a limited audience, most of which already own at least one truck. Personally, I think
http://www.collectorcartraderonline.com/ is one of the best places to list a car for sale. I think you should also consider dealsonwheels.com, coloradoK5.com, pirate4x4.com, your local "shopper" paper and your local area board on craigslist.org. Ebay works for some, but not all.
Blazers tend to sell better in the spring and summer. In the cooler areas of the US, we can't run topless in this season and one of the main attractions to an early K5 is the removable top. Keep trying, as rolled72 mentioned, someone might be figuring out a way to buy it right now. When I bought my '72 from a board member, it took me a while to convince my wife it would be a good idea and determine if and how we could afford it.