I think in the episode where House recounts the story of the janitor/healer he encountered when he was younger was revealed to be a lie of his. Though I could
see him working in that capacity.
Earlier this season House managed to acquire a large sum of money through a bout of insider trading which he used to partly fund his department again. It's possible he has enough of this money left over -and access to it inside of an account or form he can still get to considering he's not "himself" anymore- to live the rest of his life relative comfort.
But he certainly wouldn't be living in America anymore where it'd be pretty hard for him to stay under the RADAR in a false identity and if he was smart he'd live in a non-extradition country where if he was found out the authorities couldn't get to him. So if he has a decent sum of money it's possible he could work in some second-world country in relative comfort and, yeah, maybe be the "wise janitor" in a hospital in that country.