Like many survivors of the proverbial long, strange trip of the '60s, guitarist Jorma Kaukonen and bassist Jack Casady have maintained the journey, switching the itinerary and the means of transportation along with the intensity, certainly, but nevertheless still on the road. The pair played together as teenagers in the D.C. area, then reunited in San Francisco, where they became integral parts of one of the iconic psychedelic-era bands, the Jefferson Airplane. They started Hot Tuna as a side project in which they could indulge their love for country blues and folk infiltrated with gospel, jazz, and bluegrass. That's still the core of their sound lo these many eons later. Hot Tuna's existence has ebbed and flowed, along with acoustic and electric emphases and a succession of band members. Also along the way, Kaukonen's 2002 solo album, Blue Country Heart, was nominated for a Grammy. His latest, River of Time, recorded at Levon Helm's studio and released last winter on St. Paul's Red House Records, continues in a similar vein with fine covers of blues and country classics as well as a handful of deeply ruminative originals, all tricked out with exemplary picking. Expect a Tuna casserole of wide-ranging material.