One thing I've noticed about almost all the postcards I've looked at is very few of them have any dates or any copyright information on them. Hmm.
Here is a prime example. I know this postcard is not current (duh!), but the only way I can figure out when it's from is to try and identify the cars in the photo. The blue car looks like something from the early 60s.
It's definitely before state tourism departments got as slick as they are now. You can tell that by the (lack of) photo art direction on the front or the straightforward copy on the back.