The T-1 was used just for airways nav training, in the intermediate phase, as were the T-39G's. The T-39N could be used for airways nav or low level, Radar Nav, or air-air Radar intercepts, as the N model has the APG-66 in the Nose. T-1's are not used up in the advanced phase, just the T-39. T-1 can't support the payload in the nose, nor should it.
I loved flying the Sabreliner, it was one of my all time favorites, until I got a type in the 747, they behave very similarly in many phases of flight, and share some flight instruments, it was an easy transition.
My thoughts and prayers go out to those left behind by the VT-86 crew, they are going through unspeakable challenges and have many questions.