My daughter had an LGA Delta flight (terminal C), and I had a Southwest flight (terminal B). I wanted to go over to her terminal so we could get a cab into Manhattan together... it took about 45-50 minutes to get from terminal B to terminal C! On the return trip it was the same.
It's lots of walking (probably a mile at least) and lots of navigating....up and down escalators, reading signs, and catching a shuttle that was a 15-20 min wait, mixed with ride and park, hotel and employee shuttles.
Next time, if its anyone other than my daughter, I will tell them to just meet me in the city. It felt like a mini marathon lol. I wish I wore athletic shoes!