How do I keep track of characterization in my story if I have to take a hiatus from story writing?

I just finished writing the first draft of my original story. The only thing I have left to do is to edit for grammatical errors and type up parts of the story that has been handwritten (most of the story has already been typed).

Due to personal reasons, I need to take a hiatus of at least one year from fiction writing. I might write a sequel to my original story and would like to remember how my main characters were characterized (speech pattern, personality, etc.). Is there a easy way I could do that?

Ideally, I am looking for a 1–2 page worksheet that I could fill out for each character, but I don’t know what items to include for the characters’ description nor how much detail I really need to record.

Also, is there anything I should do to facilitate my return to fiction writing when the time comes?