Funny how reliability is mentioned everywhere in firearms, yet neglected when talking about a bug out vehicle. What vehicle is more maintained, what one has a better track record with you.
I have an Explorer, a Ranger, and a little Subaru sports car. If I were to ever make that gut wrenching trips what would I choose? The one that has proven itself to be the most reliable (which is the Subaru...sadly...cause I am a Ford guy).
But to answer your question, I would go with the Suburban. Much more liable to snake its way through whatever this theoretical scenario has to offer. Taking both is also a wise decision. If you are really concerned find a buddy who also shares your interest and make a plan. You drive my RV while I follow or lead sort of deal.
If you're one in a million, there are over six thousand people exactly like you.