I'm in for November
What about the Innerleithen red route which is just down the valley from Glentress.
I've never done it but its been recently reclassified red with black optional bits as opposed to all black before they bypassed the scary black bits. Can be cold and exposed on the top apparently but no place in Scotland in November is going to be warm.
Alternatively what about a classic circuit of the Pentland hills near Edinburgh. Old school mtb'ing for the likes of the Ken, Dave and myself.
I have a recommended circuit from the village of Carlops extracted from a copy of MBR but this can also begin from the North side of the hills nearer to you West coast types !
After that i'll happily drag myself to Carron Valley/Glentress or if the the weathers mild further afield. I'd love to give Newcastlton a go or the Justice Trail at Jedburgh or Loch Ard Forrest by Aberfoyle or even England just at Keilder !!!!!!
look forward to your ideas