I've been doing the swim training by myself with some technique help from a couple of friends who were collegiate swimmers and have done a lot of coaching (one for triathletes). My biking is a mix between road and mountain, which I usually do on my own with about one spinning class a week due to time constraints. I almost always run with friends, as that helps me push through it, since running is definately my weakest area. Next week I'm planning on going with a friend to her triclub's training brick for the first time and see if that's something I want to do. (not too sure about this, though, as I'm really competitive and have a tendency to get frustrated if I can't keep up). We'll see if it works.