That's a cool theme !  :D[@Oz]

Ok, I'm going to lay out what I could see happening in the near-story-future. (Yes that's a word I just made it up.)  (Kidding.  I know that ain't no word and hyphens don't make it so. xD )

So after the battle between David and Flora, I can see the new trainers moving out of Anvil.  On to the next route, for new pokemon encounters.  

Should there/is there limits for pokemon encounters on routes?  This I don't know.  

Also, I'm not sure how many routes there are between Anvil and the First Gym.