We've been playing a lot outside, seeing as he hasn't tried to climb the fence or shown any interest in climbing the fence in just over 3 months. And since his new default behavior when he's scared outside is to run to the deck and wait to go inside, before recovering and coming back into the yard to play some more, we've been spending a lot more time outside playing.
About 2 weeks ago Sonny started breaking out of his crate a bit, and that's about the time he started showing more interest in playing, so I put two and two together and guessed that he was just letting me know he was ready for more exercise and interaction. So we've been playing a lot more, him with me and him with Roxy and Buster, and he's been eating every meal out of a work-to-eat toy. His favorite one right now is the Atomic Treat Ball from SitStay.com. He likes to move it around in his crate and watch the treats fall out, and pick it up in his mouth and drop it so the treats fall out.... it's really cute to watch him, I can actually see his brain working to figure it out. I also tried the Tricky Treat Ball from Omega Paw, but he had a much harder time with it.
Anyway, here he is, playing in the yard, leaping and hopping around like a bunny and enjoying the fresh air.
I briefly started clicker training with him, as well. He's surprisingly not afraid of the noise the clicker makes, but he's still a bit hesitant in general so we haven't had a lot of success yet. I usually spend just a couple of minutes a day when he's really excited and interested in approaching me to work on some hand targeting. I just sort of capitalize on his excitement and playfulness because I've found if he's exploring quietly and I try to engage him, he gets a bit suspicious and wanders back to his crate.
So, all-in-all we are seeing some progress. It's minimal, but progress nonetheless.