What do I need to do in order to move to Colorado?

The weather… eh. It’s definitely not moderate, like San Francisco, but it’s actually sunnier. Our summers are pretty hot (it’s been between 95–100 at least every day for about a month now, and it’ll stay that way through August, and probably won’t get cooler than 75 until October). Our winters aren’t really that cold (nothing at all like Chicago or Boston); most of the snow happens in the mountains, which you’ll be east of, and the snow that does happen it melts within 2 days. Most days in the winter, I just wear jeans, a long-sleeved shirt, closed toe/heal shoes, and carry a hoodie with me in case it changes. Maybe a scarf if it’s a bit nippy out. The weather can change really fast, but when it does, it’s often a very temporary change – we get a lot of 15 minute rain showers and 3 hour snow storms. I personally just dress for whatever weather it is right then, and have a hoodie in my car. Some people are always “prepared” for the weather to change, but I find that to be a bit tedious for my style – if it snows randomly, I’ll just be really freaking cold for the 5 minutes it takes me to get to my car, but I won’t die or even catch cold.
Every three or four years, there’s a blizzard (we were due for one last year, so this year…). A few years ago, there were like, seven blizzards in a three week span. Most of it melts pretty quickly, but there’s going to be a few parking spaces at every parking lot that have all the mountains of snow. It’s not like Michigan, where it snows, and then there’s just snow on the ground until spring. But, I don’t have any “snow” clothing, because I don’t ski/snowboard, so I just make due with a knit hat, scarf, and winter peacoat. Last year, we one day that was the coldest it’s been in 40 years (-20 degrees), and everyone just stayed home for two days.
Basically, there’s no spring or fall. There’s winter, and there’s summer, and there are summery days in winter, and occasionally a winter day in summer. But this 65 degree weather? Not so much. Spring and fall get about a week each.

If you’re from Kansas, the weather in good ol’ CO will probably be pretty tame to you, particularly if you’re living on the I-25 corridor, which it sounds like you will. If you’re looking to use your environmental studies degree, I would recommend being within a good bike ride of Boulder.
In terms of legality and credit issues, be prepared to switch banks (I always recommended 1stBank, but I’ve been away for a few years. Still, 1st Bank always served me well). You should also know that your auto insurance will go up, no matter where you come from. Due to the nature of roads in CO (and probably the vagaries of insurance law), you can expect to pay more to insure your automobile. You also need to get new Colorado plates within 60 days of settling, though your drivers license from KS will last you up to a year.
In terms of other things you need to do, spend some time driving in the mountains. You’re surely used to driving in snow, so you’ll have a real advantage over some people who move to CO, but get used to the grade in the mountains. You’ll thank me.
Other than that, have a lot of fun. I know I did.

Different cook books. Food cooks much slower at higher altitudes.

@Cruiser Nah, most cook books have higher altitude adjustments in them. It might be little asterisks on certain recipes, it might be a couple of pages in the beginning saying “add x number of minutes to baking time for every x ounces” or whatever. Or, you just learn to test the food before pronouncing it done – you bite the pasta and make sure it’s al dente, you stick a knife or toothpick in the quiche/brownie/cake, etc. Or like me, you just say “eh, good enough”.

I suggest you make sure you have plenty of employment opportunities before you go, if not an actual job. The unemployment rate is high in Colorado, just as everywhere else, unless you have enough money saved up to be self supporting for up to six months.