I concur. You'll enjoy the dry air and next winter your kids will love the snow.
It shouldn't take too long to sell the house in Katy. There are lots of nice places to live in OK city.
I wouldn't even bring up the "other platforms" issues right now. Just get the job, go in with a "can do" attitude and do them a good job. If they're decent people and you do them a good job, there will be training and another job opportunity after the Tandem stuff is done.
In the meantime, use the resources of the company to train yourself. Especially while you're separated from the family, in the transition time. I'm sure they have extra manuals, access to servers, etc. that you can use to make yourself indispensible in both Tandem AND another platform.
A couple of months ago, the OK convention and visitors bureau was advertising OK on TV, so I'll try to find the website so you can mail off for some "touristy" stuff.
God Bless and Good Luck.