Well, I can't insert Pokemon Centre, Mart or Gym's very well... The Mart and the PC use the same buildings, but different colours, so I'm a bit hesitant at editing them...
you can do the stairs tiles, i struggle with them to but lets try and do them (remember to keep backups)
anyway i can insert kyledoves d/p house like the ones in pounder zeikku's rombase.
Do you want to do that or shall I? I do have 1 little inserting problem. I can't insert buildings that well... I'll probably get better though, so ignore my ramblings.