We had a great time spending a short stay in Carol's place. The apartment is very conveniently located at the bottom of the Royal Mile, a short walk up to the centre of Old Town, the Castle and many other attractions (we loved Camera Obscura). The flat itself is very clean and well-maintained, although there is some litter in the common area courtyard outside the flat (which seems to come from a neighbouring restaurant kitchen).
The beds are comfy (two double beds, and the option to use a sofa bed in the living room) and Carol leaves some Scottish biscuits and tea / coffee out for your arrival - a nice touch which makes staying all the more pleasant. All in, a great location for a family looking to experience Edinburgh.