We live in a 3 storey end town house and it is perfectly fine. No different to living in most other prprties surely? Yes we have a extra flight of stairs but it is only an extra 10 steps or so.
We moved here from a one floor apartment so was a bigger step than for most.
We moved here when DD was 3.5y and it has always been great.
Our set up is:
Ground floor: garage, toilet, utility and garden room. Garden room is cureently the dining room. This room has patio doors leading into the garden. There is also a back door leading to the garden but we never use this.
First floor: kitchen and living room. W did have the dining room in the large living room/diner, but are trying it different for a few weeks at present.
Second floor: 3 bedrooms, one ensuite, plus family bathroom. At present DD uses the third bedroom as her playroom, but it also has a sofa bed in for when our friends stay.
In the past we had the playroom in the garden room also, before the change round.
The garden can be accessed from the side too, and we have a gate wth a bolt which is padlocked on it.
WE have never really thought of any of it as a problem. DD has just played wherever, or in the garden, and I have just listened out for her on and off.
Only issue with toddlers we have found is that you would need to have more stair gates than in a normal house, and would probably make more use of a baby monitor.
I think ALL the townhouses round here have families with children in them!