The guide was fine. I'm relatively new to mapping, and I read it (all) and found it helpful.
As for length, watch any decent "intro to mapping/radiant" series of videos on youtube, have a think about how deep they go, and how many words they use. Yes, you do need to do a lot of writing to adequately cover everything in a crash course, people are just unaccustomed to seing something of that scope in text.
Yes, it was first person and a bit of an ego trip in places, but that didn't bother me.