Yes, I have seen the Dead at the very small Sacramento Memorial Auditorium. No I didn't see this show. It would have been cool if both bands played Sitting on Top of The World.
Mick Martin wrote an excellent review. Wonder where you are now??
The show with Cream was the Dead's second Sactramento appearance. The first was at the Beaux Arts Ball in December, 1966
And the Dead also played another show on 10-5-1968 in Sacramento at discussed here in the Express on October 10. I have only seen the Youngbloods listed before and not the other groups