I have been taking lots of quick trips with Chimera to either take a walk (and work on polite leash walking, of course), or to work on focus in a new environment. We've gone to different grocery stores, a couple of parks, and some residential streets. I used to do this a lot when he was a puppy, but stopped almost completely when his reactivity became full-blown Monster.
I have been pleasantly surprised by how well he is able to focus and think. I only ask him to "work" if there isn't any activity going on, but even so, I was expecting him to be too distracted by smelling everything and looking all around. Instead, when I ask him if he wants to work, he happily answers that yes, he does. At this point I ask him to do one or maybe two behaviors he knows well, give him a treat, and then release him to "be a dog" until he tells me he is ready to work again. It goes quite quickly.
I think this improvement is due to a) our reactivity work making him less worried about the environment, b) some impulse control and distraction games we've been playing at home carrying over, and c) as always, the dog simply maturing and settling down is a factor.
I'm now able to look forward to our continuing focus and ring prep work, since it doesn't feel like it will be such a struggle anymore.