If we Oregonians were famous for anything, it was an old, old trail we'd had to blaze to get here. Since then, things had been pretty tame.
In this sentence, why did the writer not use "have" instead of "had"? I found it in the book whose title is "Shoe Dog" by Phil Knight.
I can't say for certain why an author chose certain words, but here it would seem that "things had been pretty tame" implies that eventually things stopped being tame at some point in the past. Perhaps the sentences that follow your quote illustrate how the calm period of time following the Oregon Trail came to an end.
"Things have been pretty tame" would imply that the calm period following the Oregon Trail continued all the way to whenever the statement was made.
sequence of tenses:
had been precedes became poor. Please see below.
"we have had to blaze a trail" would refer to the present: We have had to blaze a trail to get here.
In your sentence, anything that precedes "was an old, old trail" occurred before the point in time when the trail became old. The trail had to be blazed before it could become old. It became an old trail after it was blazed. Everything is in the past.
Imagine a line with:L before some past | some past | present |future.
the old trail is past and the had had to blaze comes before it.
