Star Trek 2 was in 2283 for Kirk's 50th birthday, but it would seem that the events of the next following movies were right after TWOK from one movie to the next so that must mean the 3 movies took place at the same time.
You can take a bit of license with each.
Between 2 and 3, the Enterprise has time to go to Ceti Alpha V to pick up Reliant's crew, drop off most of her trainees, and for Spock's death to enter the long term grief phase. Say anything between a couple of weeks and three months?
Between 3 and 4 I'd infer they have been on Vulcan for at least a few months, enough time to completely refit the bridge, for Spo.k to be re-educated and so on. Maybe anything from about 3 months to a year?