"Blueberry" was one of my favorite comics when I was a teenager, and along with "XIII" inspired me so much so as to go on and spend 7 years trying to write my first novel (which ended up being a 700-page stylistic mess, I'm afraid).
In any way, what you've read of the story are really the best parts. The first five albums make up the "Fort Navajo" cycle, which is a very long and somewhat traditional western with a lot of twists that is somewhat hard to get through.
I've never read the "railway saga" that followed it, chiefly because I missed some of the hard to track back-issues that reprinted them here in Serbia. Everything following that, starting out with the search for the lost mine was very inspired and made me re-read it time after time.
With "Arizona love" the series pretty much ends, with story picking up in several spin-offs. There's a "Young Bluberry" series, really a series of short stories, that details his experiences during Civil war, constantly changing sides in a fashion as confusing as Fort Navajo. Among those is a tale of how Blueberry got his nose broken which is an amusing anecdote, but nothing more than that.
There is also a "Marshal Bluberry" series, made up of 3 albums that spotlight the art of "XIII"'s Vance, also a non-essential tale that takes place after the events of the treasure-hunt cycle that you've reviewed.
The last entry in the series has been "Mister Blueberry", about Blueberry's last days as a gambler in Tombstone. Just like "Marshal Blueberry", I found it an interesting side note, mainly for Giraud's art.
Any way you look at it, "Blueberry"'s a major comics release, and is sure to stand the test of time as a premiere Europian western comic.