I have now taken the first steps to doing something concrete.
I have finally got around to collecting all the old files, maps and folders together and seeing what was what and have gone over the material at hand.
There is a lot there but not as much as I originally thought. It seems a lot more than I had realised was in my head rather than being written down.
The first thing I am going to do therefore is to get some notes down on what I can still remember that isn't already. That unfortunately won't take too long.
I have also made steps towards organising the solo campaign, but early days there too.