Dude that sounds absolutely hellish.The secret is to go back up every time you go down a new flight. So, down one and then back up. Then down two and up one becomes the pattern. You've increased the number of steps by quite a bit on the way down. It doesn't seem like it though because you aren't trying to climb all the flights at once.
Oh, and then you get somebody else to do the reverse pattern going up the stairs. Then, you don't have to carry the kettlebell back to the small gym.