Buddy. Buddy.
You need to get yourself a 17' touring kayak, and then turn yourself loose.
Go out for an afternoon, or tour for a month.
Ocean or river. This is your boat, unless you are one of them whitewater or kayak surfing guys.
Why you want a short dayboat, and rob yourself of the potential? Where you gonna go in your 12 that you can't go in your touring rig?
You can troll for salmon in it, too.
Take a few lessons, find out what you like in a boat.
I'd personally not buy a cheap boat, because a cheap plastic hulk is no fun to paddle - and might turn you off. Plus, I hate to buy something twice. Screw it, you only live once, life's too short to pilot an ugly boat that you're not in love with.
That's a personal choice though, lots of different and valid opinions on that. Buyer beware though.
But then again I am an opinionated asshole - I can only tell you what is 'obvious' and 'right' for ME (from BC). You may have different ideas as to your needs, being in Colorado. So I guess you have to ask yourself where you want to paddle, and what you want to do.