Hotel Pamporovo is certainly walking distance - a few minutes from the centre. Other hotels that are more central are Perellk, Mourgavets and Snezhanka. They all have bars and night life seems to have centred around Daks which is round the back of Snezhanka in the past - not sure where is hot these days.
Transfer is about 3.5 hours from Sofia (less if good weather and more if bad) and about 1.5 from Plovdiv.
quite a few do now - certainly the main green from the top to bottom is completely canonised (is that a word?) and there are some canons on the stoikite runs and scattered throughout the rest of the mountain.