If you'd like to see what Donn's BASIC was like, you can! The Internet Archive has a version that runs in-browser [1].
Although the Folklore article says there were two books describing Donn's BASIC, I believe there were at least three: Introduction to Macintosh BASIC, Using Macintosh BASIC, and The Macintosh BASIC Handbook. All three are available at vintageapple.org [2].
An interesting, older paper that explores how to bridge the "ninja gap" between naive code and hand-optimized code is Can Traditional Programming Bridge the Ninja Performance Gap for Parallel Computing Applications? <https://web.eecs.umich.edu/~msmelyan/papers/isca-2012-paper....>.
They reduce the ninja gap for a range of benchmarks from 24x to 1.3x by relying on "smart" compilers and using only basic program transformations---no intrinsics!
Here is a link to the version published with the ACM: <https://dl.acm.org/doi/10.1145/362375.362379>