We live in a garden, and also do delivery of furniture and stuff on base as a side business... and I can tell you that as long as we can get to the back sliding patio door, there hasn't been a piece of furniture we couldn't get inside yet.
Now.. the stairs may be another story if you are talking about big bedroom furniture. but as far as living room, you should be good to go. we have gotten queen mattresses up there with no problem... a king is a bit of a challenge depending on how bendable the mattress is. A queen non-bendable boxspring is do-able but tough. It's not generally the width of the stairs that is the problem, but the corner in which you need to get around to get to the second part of the stairs.
Something you might want to consider... just in case you haven't heard. If you have large bedroom furniture ... you may get it upstairs but you may not have the space to walk around the room once the furniture is in there. We have a queen bed, two dressers (upright, not the longer low ones) and 1 nightstand and it's about maxed out.

Just an FYI for ya..
