An over the counter tag (bull tag) is valid for a specific list of units, so you are 'limited' in where you can hunt, but there are so many units that are valid under an over the counter license you will not feel limited.... The specific units are all listed in the Colorado Big Game Regulations Brochure. What I think the DOW does a great job of, is providing all of the rules/regulations, hunting statistics, Maps, etc on the internet. What is VERY difficult is figuring it all out. I have been hunting here for almost twenty years and I still can't believe how difficult all of the rules/regs, draw procedures, etc are to get completely figured out.
And like a few have mentioned, all of the agents I have bumped in to in the field have all been exceptionally helpful to suggest units to hunt along with other helpful info . And the nicer you are to them the nicer they will be in return.
In terms of actually figuring out and patterning elk, you are on the right track by just spending time outside. If you can find a herd of elk to watch, even if the elk won't be there during hunting season, you will learn a ton by just watching them. And i'm talking all day. Ideally, it will be a spot where you plan to hunt in the fall... Try and get somewhere where the elk are bedded down mid-day, get a good set of binoc's and just watch them. You will be amazed at how much you learn, and watching elk is just plain fun anyways. The goal is to learn how elk behave, but it doesn't hurt to do it where you want to hunt, and come up with a game plan for opening day.
When you cannot be outside (like right now .. snowing like a dog!), spend time on the DOW website. They have a section called "elk hunting university" which actually has some great bits of info.
Then I would go to the "harvest statistics" page <http://wildlife.state.co.us/Hunting/BigGame/Statistics/Pages/Statistics.aspx> and from there you can get an amazing amount of info. Every area is listed for tag quotes, tag success rates, hunting success rates, etc etc all broken down by species.
And I also have found that the Colorado Hunting Atlas is the best map source for internet scouting since you can use the tools to measure distances, areas, elevations, etc <http://ndis.nrel.colostate.edu/huntingatlas/> (the link is also on the main page to the DOW)
Good luck!