My general attitude toward TCU is if I could climb above it, then I'll
fly through it. In a 172SP, that means it has to be under about 14,000
feet tall. On long x-countries, I'll generally cruise at 9,000 or
10,000 feet, and have not really encountered anything beyond light to
moderate chop in a cumulus cloud. Generally I'll fly through the ones
that are at most 1,000 - 2,000 feet above me... anything taller, and
I'll request a deviation.

Things definitely get more "interesting" when trying to fly through a
maze of TCUs tho. Without onboard weather scope, I'd say it's safer to
land and wait it out (or if you've got an approach controller who's on
the ball, they may be able to lead you safely through the maze).