Forgive the pre amble . I have been up a fair bit over the years and been to all of the resorts several times as well as doing some touring. I have usually been for the day ( a long one but doable from here ) or stayed at prebooked accommodation near one of the areas and made the most of what's there on the day , top draw ski , rainy walk , mtb , wall etc . I want to organise a short trip that would mainly be for piste skiing if in . I realise that chances are there will be little or no snow but this isn't a problem .
So my latest thought is to pre book some accommodation ( hut, bunk house even cottage ) that would would be central to and allow similar journey times to all the resorts . Thus allowing the choice of venue to made on the morning .
I suspect somewhere equidistant from all the ski areas (timewise) would probably be somewhere like Perth or Stirling but you would have to travel regardless of conditions
Another option would be somewhere like Newtonmore more or less midway between Aonach Mor & Cairngorm (so one eastern & one western ski area) and well placed for a lot of touring. Not so good for Glenshee or the Lecht though.