Spent the last couple of years racing road (crits/RRs), and MTB (3 hour marathon last year/Cat 2 and 1 this year) and almost completely neglecting my love of camping.  Have decided that what I really like to do is ride long and (mostly) alone.  Plus, I want to camp more.  Seems like the Ultra scene and/or some good high pace (think fast-packing for those who prefer to camp on the hoof) bikepacking could be the ticket for me.  So, I'm wonderning how some of you train for the ultra events?  Are you spending most of your training time just building endurance/toughness, or are you mixing it up with some tempo rides and anaerobic training?  Have to admit, I enjoy the endurance and tempo training, but not much for the anaerobic.  I appreciate your insights!