Backpacker....try some of the old Uriah Heep, Deep Purple, Savoy Brown, King Crimson, Humble Pie, etc. I am an "oldies freak," and I love the looooonnggg jams they got into in the late 60's and early 70's. The allman Brothers (Mountain Jam 33 minutes), Deep Purple (Space Trucking (24 minutes), Rare Earth (Get Ready 30 minutes)(Ma 39 minutes), things like that. The Grateful Dead wasn't the only one doing long jams!! Search Archive.org for all the free downloadable music you want!! I have about 70 Gigabytes worth of the old stuff!!