This sounds interesting. please keep it up. Putting him at one place sounds great idea. I would rather suggest to put Wise begger at Riften or Whiterun. Solitude is nice place to find him, but he cannot sleep outside. I think it is too cold. (I'm not sure if he has a home) plus, there is thieves guild in Riften. I remember connection between thieves and beggars. Riften is their base and seinding wise begger as their ears and eyes to Whiterun also seems probable for me.