Easy to get from Mandalay by taxi but I'd recommend renting a motorbike to be more independent. Visiting Inwa doesn't take too long, a couple of hours tops. It's a bit dirty though.
I'V BEEN THERE BEFORE WHEN I WAS SIX YEARS OLD IN 2006, BUT ONLY MY DAD GOT TO GO UP TO THE TOP. HE SAID THAT THE STAIR CASE WAS DARK SO IT WAS HARD TO SEE. he also said that (it was slanted) and some of the stairs were so steep it was even hard for him too climb.