When it comes to The Stairway to Heaven, the hardest thing for me is honestly the sheer volume of characters. For the humans, it's not really a problem. The issue is giving all the different Pokemon, especially those that reoccur, distinct and interesting personalities.
For my comic project, a lot of the trouble I have comes from working in a medium I'm not very familiar with. It makes putting the story together a bit trickier than for ordinary prose. I'm managing though :')