I know that there is an elevator to help people in wheelchairs access the Acropolis. Is it wheelchair only though? My wife has had two total knee replacements and, while she can get around, she nonetheless has trouble at times with stairs (especially when there are a LOT of them). Any chance she would be allowed to use the elevator to reach the top?
Read through this carefully: http://tinyurl.com/k4xxnks
Do check in advance. I was on the Acropolis this afternoon, and saw the elevator at the top. It was closed and access was chained off, so my guess is that you need to make arrangements ahead of time. There aren't a lot of stairs, however there is a long uphill walk to get to the stairs (and downhill as well, of course). Take into account that while there are paved walks up top, there are places where you'll need to negotiate uneven ground.
When I visited the Acropolis 10 years or so ago we were warned that The path and steps up to thehill are marble and can be slippery - in fact one of our group did take a tumble, luckily on the path, no damage.