Here I'll just note a couple date corrections for early 1968.
1.
It's true. You can check for yourself:
http://www.archive.org/details/gd1968-01-22.sbd.miller.97342.sbeok.flac16
http://www.archive.org/details/gd68-03-31.aud.cotsman.14913.sbeok.shnf
Some enterprising soul can do a more complete patch of Caution using the extra four minutes in the "3/31" source. But there is still a big chunk missing - including most of the vocals - in the gap.
[UPDATE: I've changed my mind about this - see the Comments. The older copy of 1/22/68 has the actual end of the show.]
Aside from the strange misdating, I think this fragment illustrates that the Dead were "audience-taping" their own Anthem shows at the same time they were recording SBDs. I know I read an interview somewhere where it was said the Dead set up room mics at those shows, to try to better capture the live sound - I can't find the interview now, though. [see Comments]
This also raises the possibility that our 3/68 Carousel "audience" recordings were ALSO taped by the Dead themselves. It's long been a mystery how such a series of high-quality audience tapes could come from the lo-fi days of early '68, but it makes more sense if the Dead arranged the taping themselves. (A Bear experiment, perhaps? - he was the Carousel soundman at the time, and had every motivation to record.)
Those who might scoff at the idea that the Dead, with all their piles of tapes, would set up audience mikes at the same time they were taping the SBDs, should recall that even years later in summer '73, Garcia was still having Kidd Candelario make "AUD" recordings of some shows alongside the SBD reels! These are a couple examples that have surfaced:
http://www.archive.org/details/gd1973-06-30.aud.weiner.100346.flac16
http://www.archive.org/details/gd1973-07-28.aud.weiner.106794.flac16
From the notes: "Reels dubbed in 1979 by Will Boswell from Jerry Garcia's personal collection. Original recording made by the sound crew at the soundboard."
2.
Miller has also noticed that on Dick Latvala's 1968 DATs, Latvala attributed our 3/26/68 recording to the 3/29 Carousel show.
I'm not positive about this - no songs are duplicated, but the sound isn't quite the same. The "3/26" tape has much less echo than the later Carousel recordings.
http://www.archive.org/details/gd68-03-26.aud.cotsman.6029.sbeok.shnf
http://www.archive.org/details/gd68-03-29.aud.vernon.9473.sbeok.shnf
In any case, our "3/26" show is definitely NOT from the Melodyland in Anaheim, as the Archive file claims! (Though the band had played there earlier that month.) The Dead, as far as we know, did not play the Carousel or anywhere else on March 26. So presumably the "3/26" tape comes from one of the Carousel dates of 3/29 - 3/31 - though it could be from any unattributed show that month.
(More details on the Dead's March '68 schedule are here -
http://lostlivedead.blogspot.com/2010/04/grateful-dead-tour-itinerary-march.html )
3.
Our Seattle shows dated 1/22 and 1/23/68 are actually from 1/26 and 1/27. (Apparently they were misdated on the original Dead reels, as the new Road Trips material still bears the date "1/23".)
This has been conjectured for some time - deadlists, for instance, has a note about the dating question:
"No documentary evidence (posters, reviews, newspaper ads, etc) has been found for shows there [in Seattle] during the Quick and the Dead tour, other than the two on 1/26 and 1/27. Joe Jupille researched the University of Washington Daily and the Seattle Post-Intelligencer newspapers and only found an ad for QMS and the Dead on 1/26 and 1/27 in the 1/26/68 edition of the Seattle Post-Intelligencer... He turned up no mention of other Quick and the Dead shows at Eagles Auditorium."
If there were shows on the 22nd and 23rd, they weren't in Seattle. (For clarity's sake, though, I still use the old "1/22" label!)
This post on another blog covers the issue fully, so I'll refer you there:
http://jgmf.blogspot.com/2010/05/gd-at-eagles-auditorium-seattle-wa.html
4.
Our Spanish Jam fragment dated 1/27/68 - is indeed from 1/27, and completes the Spanish Jam that is cut on our "1/23" tape.
http://www.archive.org/details/gd1968-01-23.sbd.miller.97343.sbeok.flac16
http://www.archive.org/details/gd1968-01-27.sbd.miller.97344.sbeok.flac16
It's not totally certain that this is the same performance (and it has been debated), but I think it's very likely, especially once the dates match.
The "1/23" jam cuts off just as the Spanish theme is heating up. 1/27 picks up at almost the same point in the music, with apparently little missing. It's true that it makes for a very long Spanish jam (at over 18 minutes, by far the longest of the tour) - but consider, it's the last song of the show, and they do seem to be dragging it out quite a bit. The length includes a fair bit of space - and the next longest Spanish jam, from 1/17, also comes at the end of a set.
It's been pointed out that at the end, you can faintly hear Garcia saying, "See you next time we're in Seattle" (though I can't make out the next words) - which pretty much confirms that this tape fragment captures the ending of the 1/27 show, as that was their last Seattle date on that tour.
The biggest argument against the match is the different sound mix. But the sonic difference isn't that great - one listener found that the 1/27 tape has the stereo image reversed from the "1/23" tape. Simply switch left to right when you compare sources, and they're much more similar.
I'm not too troubled by this discrepancy. As we've seen, the "3/31" tape, sounding completely different from our 1/22 recording, nonetheless turned out to be exactly the same show, from a different source! And nobody could have known until Miller gave us the complete 1/22. And there, too, the Caution has that tapecut so we have a gap in there as well.... (This is a tour especially prone to tapecuts and short reels.)
In the case of 1/27 though, we can't really be positive that the Spanish interruption is just a tapeflip and not two separate performances, unless a more complete source turns up. But my feeling is it's the same show.
