He may not be retiring, but he's certainly tired of touring, based on his own statements.
Phil and Jill Lesh were posting on ratdog.org on 12/4/2010 (Source: ratdog.org/community/viewtopic.php?f=1&t=269688
). Here are some snippets, decide for yourself...
"We have often thought it would be easier and more fun to have a small venue close to home and retire from the road."
"...it would be a positive thing to be able to make music every week end and go home instead of bouncing around on a bus."
TylerTerrapin asked, "When are we going to get a Railroad Earth - Furthur tour." - philandjill replied, "Don't know about a tour, but when I get that small venue close to home, they will definitely be on the invite list."
Rutil8ed posted this in the same thread on 12/4/2010 as well, even before Phil Lesh announced that Terrapin Landing was based on Levon's Ramble: "I like the idea of you guys smelling the roses and taking the full time show off the road and into a more intimate Bay Area venue. Perhaps a west coast version of Levon's Ramble?"