Resuming a Classic-Era Cthulhu Campaign

After some discussion with the group, for our Call of Cthulhu game we decided to bring back some characters from our campaign which took place in 1918-1919, beginning with an adventure set during the Great War (Chaosium's No Mans' Land).

I've been giving some thoughts as to the best way to do this. It's been about two years in real time since we last played that game. I'm definitely going to take advantage of that gap and will be introducing a one to two year gap in the game as well, pushing the timeline to 1920 or 1921. I think the passage in time can be used for a number of purposes.

We've three regular players in the game plus myself. One of the players has decided to go for a new character, having recently torn through HP Lovecraft's works (having previous familiarity form the game) - he's been eyeing an antiquarian. Another of the characters has been learning about the Cthulhu Mythos, having delved into the Book of Eibon. That time is useful to give him time to fully read the tome and to learn a spell or two. He's also a bit on the unstable side and may be able to take advantage of that downtime to indulge in some sanity-boosting activities to delay the inevitable slide into madness. Finally we've a young budding librarian from Harlem who might spend some time studying at the Miskatonic University.

As I review our old campaign material and consider where to go from there I'm reminded of a few ideas I had from our previous game. The first of which is that HP Lovecraft was an unreliable narrator. The stories he wrote were true... to the best of his knowledge. This means names, dates, and places may have some inaccuracies to them. This means, for example, it might be our characters who face "The Dunwich Horror" - and it also means the dates ascribed to his tales might be wrong. If it serves the campaign to have the raid on Innsmouth take place in 1921 then we can do so.