TexasCHLforum.com

Interestingly it seems that unlicensed, non-residents will be allowed to carry in their vehicles - mental health check or not.

Having looked at the list of 22 places off limits for carry I don't think my trips to Illinois would be materially different if I had one of their non-resident licenses ($300 plus living in a state with a "substantially similar" law) or just opted to keep it in my car ($0).