Against all odds, I made it to the barn last night for about 1.5 hours in the middle of a 14 hour workday. I even beat evening grain, which doesn't always happen!
We free-longed again and he is getting even better. We had one or two incidents early on, and near-ish to the end when he was getting bored and sick of me he let fly with his hind end in my direction and took off, but he regretted it. (You want to run, pony? Go ahead, keep running!)
I like free longeing right now; even though I still can't grip a longe line, I can get and keep him moving, and he travels the entire circumference of the indoor, so it's easier on his joints. I can control his stride and keep him forward, and praise when he stretches down. It's even a little bit of exercise for me as I jog alongside him in the trot. And it's great for our communication: by the end of the session he was adjusting his gait and position by my body language alone, and his response to voice commands had sharpened up considerably.
We did 10 minutes of walk each direction, 5 minutes of trot each direction, 2.5 minutes of walk-trot transitions both directions, and then a few minutes of trot-canter transitions; I didn't time those. I basically ran him through a few until I felt he was responsive and had a smoother transition and then called it quits. I wanted to drill the walk-trot more for muscle-building purposes.
Tonight, hopefully more of the same, and then out of town for four days - of course, four of the nicest days we've had in months. It might even hit 40!