With breed preferences, I have none. I generally love all dogs but it does depend on their personality. As for what I want to know, I'd prefer to know as much as I can; past injuries, medical conditions, likes and dislikes and anything else I might need to let the dog have a good experience.

For big dogs, I try to find a nice forested area with clearings so i can throw a ball for them, it lets them explore but also get the exercise they need, smaller dogs usually just a casual walk through town or a park area, I've found being close to nature is helpful to calm dogs in general. Activities usually include playing fetch or tug of war and often letting them just smell around and explore. But I of course would ask the owners their preferences for activities or walking areas their pet, since they know it best.