When people go with distance, there are two examples we can use. What Devalue posted is actually really good. But anyway:
For we know Ash had been with Pikachu for about a year by the time we get to the third movie. Which is when they are in the Johto region. Kanto is not the biggest region and is honestly fairly small. The Orange Islands took about that time, If I had to guess, the islands would have taken about a month given the idea each episode is a new day and there are 36 episodes. At most, I'd say it would take around.... 2 months? Best idea is to count each episode as a day to three days. But remember that the anime, at least Kanto, is very inconsistent with time. At one point we go from Ash not having many wins to him have like 50+ wins against other trainers we never see. They are just mentioned.
Now for the second way, in the manga, Ruby and Sapphire had a contest in which would last 80 days. This was to get every gym badge or all the ribbons. They rushed the entire time so they wouldn't lose to one another. Given the size of Hoenn compared to Kanto, it would probably only take two months to go everywhere in Kanto, not including extra areas.
Now I have 1 more idea, one that I sometimes use when writing. Count the amount of steps between each town while walking and then divide by 3 or 4. I can't remember the number exactly that I used to divide by. But whatever the number is before you divide, that is how many days is between each town. This obviously takes a lot of time and you have to have every game.
As for your idea in terms of pokemon and people, your best bet is to use Serebii, go to each episode and look to the right side and it will list what pokemon appeared. What trainers ect. And if they are named trainers, go to bulbapedia and look for the trainer there.