I live in an apartment with my bunny Exempel. He is free range, but is rarely in any other room than my bedroom, where his cage is. When having a bunny inside you have to make sure it can't bite any cables.
We lived in a house before and I wouldn't say it's any differences between living in an apartment or living in a house.
#2 When we lived in the house we did have two stairs (one to the basement and one with only 4 steps) and he could jump up from the basement, but not down (luckily). The small one with 4 steps he jumped both up and down!