The subtitle says "North of Galveston 1983" and there are mountains in the background. Having grown up around the Texas Gulf Coast, I can tell you that there is not a mountain to be seen within at least two hundred miles of Galveston.
I've been to the Indian Dunes area many times, and this is indeed where the training camp sequences were filmed. Also, Chart's house / helicopter pad scenes were shot in the same general area. I believe that the Charts set is on or near the same airstrip where they filmed the TV show "Baa Baa Blacksheep," which was also filmed at Indian Dunes. Of course, the most famous thing filmed there was the infamous "Twilight Zone: The Movie" scene when the chopper crashed and killed Vic Morrow and the two kids.
I rememeber going to see this in the theater. I live just outside of Houston and when this scene came on, it got one of the biggest laughs I have heard in a movie theater.... Still a very enjoyable movie