I did take into account some of the time between stories; everytime a novel ends with "Now we finally have our two weeks of vacation on starbase 7" or "It would take a month for the Enterprise to return to the next starbase and anothertwo weeks for it to get repaired". Of course there are tons of stories that don't have such endings (or a similar beginning like "The Enterprise was on boring patrol for two weeks") and while it is extremely unrealistic that they go from one adventure to another in a span of days I just sort of accepted that. It does (mostly) work if one takes into account all information given in the novels and episodes, but it is unrealistic.
For example April 7-18, 2267 in my timeline include
The Centre Cannot Hold, "Amok Time",
Gemini, "This Side of Paradise". While I don't have specific day counts for
The Centre Cannot Hold, "Amok Time and "This Side of Paradise" I noted
Gemini taking place over a few days. Over the 12 days this time period harbours we have an average of four days per story. This technically works with the chronological information given in the stories, but ir does require some degree of suspension of disbelief because the Enterprise has to fly to like four planets that should realistically probably not in the same sector and of course there are the routine missions that never happen. Conversely December is much more relaxed; "I, Mudd" starts after the 13th of December and ends before the 18th and "Obsession" starts after the 22nd and ends before the 28th.
I had fun figuring it out, though, so it was worth it