I think Carl and TJ are fairly interchangeable as first plays. The problem I have with saying to do Leo before TJ is that Leo's has major emotional resolutions to TJ's route. And Flynn before Jenna also helps deliver an emotional climax to the characters. Jenna's route has the most closure out of all, although Leo's feels far more realistic. I personally started with Carl's but I've had people bounce off because of how they felt about his story. It's one of the weaker stories despite having some of the most lore in it.
I've played through a couple times so I've seen the added context, and I find the ideal route to be Carl - TJ - Leo/Route 65 (Flynn) - Flynn - Jenna - Route 65 (TJ route) - Leo. But considering how much that is and how people can bounce off Carl, I tend to compromise and say TJ-Leo/65-Carl-Flynn-Jenna.