DH and I have been talking about the possibility of retiring in Texas within the next few years, or at least possibly buying a mobile home in a park and wintering there. but how can I find out what basic expenses are like in Texas - such as food, gas, utilities, etc? I know that coming from Minnesota, we wouldn't have the astronomical heating bills that we have here, but would air conditioning be about the same?

Lots of questions I know.....but where can I find some answers??

Well, part of that would depend on what part of Texas youre considering moving to.
I live in Southeast Texas, and during the winter, our electric bill (3bed/2bath - no central AC or heat) runs about 175ish. But our gas bill is around 65 for the winter (we have gas heaters, dryer and water heater).
In the summer, that changes dramatically - electric is sometimes as much as 250, and gas is cheap at around 25-30.

Water runs about 75 per month for us.

Another thing to consider is insulation, trees (hence, shade) on your property, whether you will have central heating and cooling, or use window AC units and space heaters - a lot of variables :)

I think that there are websites that will tell you around how much the average cost of living is in different places. You might google it and see what comes up.
Feel free to PM if you have any questions!
Best of luck to you!