Woofless, 3500 acres?? I can't even imagine!
For our experience, I did also do a personal "census" for a while, because I was curious too. I live in a semi-urban university town nestled amidst some urban and less urban areas (I wouldn't call any of my immediate area suburban). Lots of single-family homes with small or modest backyards, which we do have, but that's not where the dogs get their exercise. Lots of people around here live in apartments with no yards, as well. So our dogs typically get daily walks around the neighborhood in the evening, and I take them to one of the local off-leash dog parks every day.
Local culture has made this a pretty dog-friendly area with lots of public use land available for canine social activity. I consider us pretty spoiled in that regard. On each average weekday, we interact with 40 ~ 70 dogs in an off-leash environment when I take them to the 23 acre dog park (over 200 Yelp check-ins since February of last year, and still counting) – but I counted both passing and actual greetings in my tally. Bowdu my Shiba is better with just a cursory sniff, while Bowpi loves to check out and gently sniff nearly every dog she sees. On the weekends, it just gets too congested at that park -- one can easily hit three digits in a one-hour visit -- so we go to some of the less dense trails, where the dog count per visit usually stays under 20.
I do not count people, but my dogs generally ignore them all equally. Unless they happen to have treats or something. 
I started counting because I wanted to get a sense for myself just how "socialized" my dogs are, relative to the number of other creatures they encounter. Truth told, I was concerned about how my Shiba in particular doesn't always get along with every dog he meets. But once I started counting, I realized that the other dogs that he gruffs at are very few and far between, and there's ALWAYS a reason -- the young, exuberant Lab who literally plowed into his side when bounding over a blind hill, the unneutered Boston Terrier who was snort-breathing in his face and wanted to push him aside to pee on all the bushes, the pack of JRT that swarmed my Basenji and made her squeal. So doing the census also helped me learn which dogs and situations to avoid, or at least anticipate.
They meet far fewer dogs on their leashed walks around the neighborhood. I can't even imagine if 40+ dogs a day was the number of LEASHED encounters -- my trouble dog is a very different beast, and not at all interested in being sociable in that situation!
It sounds to me like your Fuji is very well socialized and very sociable as well, as not every dog can be that gregarious both on leash and off. I recall that with the BRAT application, there is a section that asks you to describe your daily routine with your dog (if you have one). I'm sure you would be able to provide a convincing narrative that a backyard is not at all necessary for adequate exercise or mental stimulation. I think though that a setting with more space (which you read as "surburban" or "rural") is implied is because not every dog is psychologically equipped to deal with a flood of new social interactions -- especially not rescues, who sometimes come from unknown backgrounds. Or maybe exactly because their background is known.
My Shiba, for example, came to us as a puppy from a VERY urban, extremely populated setting, where virtually nobody has backyards and there were no dog parks (Taipei). He never learned to like it. Even when moving to the States, he had to adapt to becoming comfortable in a large range of social settings. He's less fearful now, years later, but I don't think he'll ever truly ENJOY interacting with most dogs and most people. He's happy enough sniffing his own bushes and running in his own space. I'm okay with the idea that I'm probably more interested in meeting a wide range of dogs and people than he is... and that my Basenji also has different socialization priorities. But if you threw them into an environment like the streets of Manhattan without having known anything like that before (and most living creatures in the world have NOT), well, there will be a period of acclimation, regardless...
