I'd recommend you send Keith at GDE an email and ask, he is exceptionally responsive. The 2 tunes you probably should look at are the EcoTune and the Full Torque EcoTune. I suspect the former is slightly easier on the TC than the latter. I can tell you that stoutdog and I did the I-10 run (moderately hilly sections in places) with in his 06 fully loaded with a kayak on top pulling a fully loaded 5X8 uHaul trailer (weight ca. 2,000 lbs) with zero problems on an OEM TC with the EcoTune and a basic GDE TCM tune; see
viewtopic.php?f=5&t=69117&p=739421#p739421 About all we had to do was anticipate upcoming hills with the go pedal foot a bit; if you let cruise handle things the tranny would down shift part way up a hill whereas getting a bit better run at the same hill would avoid the down shift.
I won't say it's impossible for a TC to die an abrupt death because it is but in most all cases you are going to get very obvious TC shudder under load well before a TC will go out and that shudder can be mitigated by backing off on the load as an interim solution.
Bottom line is I would spend your money on the GDE tune first and not just run out and replace the TC unless 1) money is burning a hole in your pocket or 2) you can do it yourself. I'm only running the Suncoast because I gave myself a retirement present of a GDE Stage II turbo and the required TC upgrade (that turbo would induce TC shudder instantly if you stomped the go pedal) and I went with Suncoast because 1) I did not want to do the work and 2) Suncoast would and they were not that far from home.