Got it, thanks. I believe that the version I have might be a later printing of the 1978 version, but actually the book I'm remembering most clearly was a later 1986 book by Ahl with a similar title of "Basic Computer Adventures" which has 10 longer adventure games… including an early version of Oregon trail.

https://archive.org/details/basic_computer_adventures

There was this sequel too

https://archive.org/details/More_BASIC_Computer_Games

I don't think I ever saw source code for Oregon Trail As for text adventures those require fairly exotic programming techniques to pull off. Infocom had the Z machine interpreter written in assembly for many machines but Scott Adams made an interpreter which could be implemented in either BASIC or assembly.