With your homes in Kansas City and New Mexico, it strikes me that you are already within a day's drive of the majority of places you would probably want to chase. Though you do have to be in the right house for the particular setup, of course. But I do have to say I like the idea of starting out in NM, following the weather system northeast over 2 or 3 days, then having a home in Kansas City. Sounds to me like you have a pretty good setup already.
Now as to your question, my inclination, assuming you intend to keep these two homes and want another one as a base for chasing, would be stick a pin about in the middle between them and then search Zillow or Realtor.com. That would put you somewhere in NW Oklahoma or SW Kansas, which as others have pointed out, is an ideal chase location (think Dodge City and Rozel). As an owner of 2 homes, I tend to agree with Dan that owning multiple homes is more complicated than most people think - and ours are just 3 hours apart (in CO and NM). But if you already own homes in Kansas City and New Mexico, then you know what is involved.
As to taxes in CO - what an earlier poster said about them being high may be true if you are in the big cities, but in smaller towns property taxes are modest. And Colorado's flat-rate income tax is one of the lowest in the country, and as a retiree, depending on your age, you pay no income tax at all on the first 20-24K of your income, depending on your age. So CO is actually a rather low-tax state as long as you are not paying Denver or Colorado Springs taxes. And given what it costs now to buy property there, taxes are probably the least of your worries.