If you have not already done so, I would recommend you review the Montana Gun Laws sticky thread which covers a lot of information in summary format, you can find that thread here: http://forum.opencarry.org/forums/sh...ntana-Gun-Laws.
If your more of a legal type and want to review the MCA's yourself you can view them here: http://leg.mt.gov/bills/mca_toc/45_8_3.htm
Additionally for conceal carry information you can find that at this link: http://www.handgunlaw.us/states/montana.pdf
To help answer your question. TX permits ARE recognized by MT. You indicate that your TX permit will expire before your 6 month residency requirement is met, in this case you will have to be a little more careful. After your TX permit expires, you will either have to Open Carry, Conceal Carry (outside of city limits only, 98% of MT is outside of a city boundary) or off body carry. In MT, concealed is defined as concealed under wearing apparel so if you have a phay pack, purse, backpack, glove box, center console, etc you can carry concealed in those locations and not be subject to conceal carry laws.
Once your 6 month residency is complete, then you can submit your application for a CWP at your local sheriff's office. Your existing TX Permit should satisfy the training requirements required in MT and you should not be required to take any other training classes. Just for reference, some sheriff's offices consider your residency requirement complete once you have a MT drivers license, this is not the law but you may be able to try and obtain it early. Talk to your sheriff's office to see what they say.
I hope you have a warm welcome to the state and you enjoy your new place. Kalispell is a nice place to live, I am on the other end of Flathead Lake in the Mission Valley, maybe i'll see you around.
If you have any questions or concerns feel free to ask.