Corry's original post on LLD: "Hooteroll?--When Was It Recorded?", with lots of great comments.
My response: "Response to LLD's Hooteroll--When Was It Recorded?"
A number of commenters to these posts, including sraile and LIA, as well as more from Corry, have added valuable thoughts and information. Thank you all!
The purpose of this post is to give a bit more information, based on a post from Blair Jackson at Deadnetcentral, reflecting tapes in the Garcia vault. This information disconfirms my speculation that Hooteroll? was completed by the end of 1970. It seems to have been recorded ca. October 1970 - ca. June 1971.
Here's what Blair so generously reports:
There are a couple of 2" reels with this date, which need not have been a session but could have been mixing or copying or whatever. On these tapes: two "unnamed" songs, "Up from the Desert," "A Trip to What Next" and "South Side Strut." "Personnel is definitely Jerry and Howard, plus unnamed bass, drums and flute."
What interests me here is a 10/26/70 "Jerry Garcia & Friends" listing at the Matrix (Good Times, v.3 n. 42, 10/23/70, p. 14). In years past I would have thought that GD would have just gone east from St. Louis after 10/24/70 en route to Stony Brook on 10/30. But I no longer believe this. It seems to have been Jerry's habit to come home even in 2-3 day windows, even if it meant flying twice over lots of the same terrain. This seems to have been especially the case when there are sessions back home. So I have little doubt but that he was in the Bay Area on 10/26 and even 10/29.
Was this a gig with Wales? Dunno. If so, that would obviously fall after the date on which I have speculated things started up with Merl Saunders, i.e., September 7th. (Not that it matters, but it's amazing how hard it is for me to shed the assumption of linearity in my thinking about all this.) Anyway, all of this stuff leads me to see that there was considerable overlap between Merl and Howard -- almost 17 months, by my present reckoning. It's just that (with the exception of the Hooteroll? tour in early '72), Wales & Garcia took it from the stage to the studio. Why not? There are nubby Doris Dynamites and blow o'plenty there!
Next date that appears on tape boxes. Again, need not have been a session date, though so far as I can tell Jerry seems to have been in town. Blair: "There are some reels with no titles, and also full reels with multiple false starts and a few takes of "South Side Strut" and "Up From the Desert" that were probably referenced for the mixing of the album."
Blair: "By 6/21/71 the full album mastering has been completed, and the 2-track masters (or are they copies?) are in the vault with that date on them."
Blair: "Then the next tape entry in the vault is four live multitrack reels from Boston, dated 8/1."
Whoa. Is it possible that Wales & Garcia played in Boston on Jerry's 29th birthday, August 1, 1971? Well, the GD did play Yale University (New Haven, CT) on 7/31 ... anyone ever wonder what was up with that? JG's first solo album, Garcia, was said to have been recorded in three weeks in July 1971, and then the GD go out east for a one-off. So JG almost certainly began 8/1 within easy reach of Boston ... is it possible that a Boston gig happened this late in the game, with no contemporary record or memory of it?
Anyway, this is a really interesting rabbit hole we find ourselves in, I think. I still have a million questions about all this. For now, I'll just aver that I was wrong in speculating that Hooteroll? was in the can by the end of 1970.
So I answer Corry's titular question as follows: so far as we can tell, between October 1970 and June 1971.