Just a few months after what was billed as the Grateful Dead’s last stand — five sold-out stadium shows for some 212,000 fans that grossed more than $60 million in ticket and pay-per-view sales — the band is rising once again, albeit in a slightly fractured arrangement.

This weekend, insatiable Deadheads can see all of the group’s so-called core four living members in just two stops: Madison Square Garden, which will host Dead & Company — featuring Bob Weir, Mickey Hart and Bill Kreutzmann, joined by the pop singer and guitarist John Mayer, the bassist Oteil Burbridge and the keyboardist Jeff Chimenti — for two sold-out shows on Saturday and Sunday; and at the Capitol Theater, about 30 miles north in Port Chester, N.Y., where the Dead bassist Phil Lesh will play three consecutive nights starting Friday (with another run Nov. 5 to 7).

“Only in the world of the Grateful Dead could that happen on Halloween,” said Peter Shapiro, the concert promoter who owns the Capitol and organized this summer’s “Fare Thee Well: Celebrating 50 Years of Grateful Dead” shows in Chicago and Santa Clara, Calif. The Dead had a penchant for blown-out holiday concerts, he noted, and both locales are “institutional venues” where the full band played dozens of times.

“Dead 50 wasn’t the end — it was the end of them as a unit, you won’t see that again — but the music goes on,” Mr. Shapiro said, adding that the farewell concerts “re-lit a flame under the whole tribe.”