I have Mr. Scott's Guide to the Enterprise, by the way, and it's a very nice collection of deck plans, though I don't know how accurate they are. He gets the dates all wrong, however, as he's basically making it up as he goes.
The dates in Mr. Scott's Guide
are based on those in the 1980 Star Trek Spaceflight Chronology
by Stan and Fred Goldstein. That dating system was considered official at the time, and used in the novels of the era as well as FASA's Trek RPG.
It was in the early 90's when TNG was huge, that the Okuda's Star Trek Chronology
was released, which moved around all the dates, rendering the prior book obsolete. The writers of all subsequent Treks switched to this new dating system.
Shane Johnson also wrote Worlds of the Federation
, a guide to Trek's planets (also rendered somewhat obsolete by recent canon, although still a fun read) and some unlicensed Trek books like The Star Fleet Uniform Recognition Manual
A fascinating interview with Johnson, about the creation of Mr. Scott's Guide to the Enterprise
, is here: http://www.trekplace.com/shanejohnson.html