If aliens invaded Earth disguised as humans, where would you expect to find them? What jobs would they be doing? What would be their intentions? How might you interact with them?

Well aliens have been rumored to like to do strange medical procedures on abductees so my uneducated guess of course would be finding them in the hospitals or science labs. Their intentions would be to figure out why how Otis makes his shine so quickly and it comes out perfect every time. Or what does Hippy really put in his pizzas. Or what makes Roosters beans so potent. So maybe they would be disguised as farmers to..... The world may never know!

They would be disguised as engineers or scientists so that when they went back to their homeplanet, or they met up for coffee with another alien, they would laugh about how primitive we are and how little we have discovered, and so that they know what, out of their 'advanced' technologies (that are pretty primitive compared to other 'alien' civilisations) they have to use to destroy us.

Or, they could just destroy Earth for a new hyperspace bypass.

Their very presence would verify a much greater intelligence (which wouldn't be a very high bar, anyway) and, depending on their intentions here, they might seek to put themselves in positions to exert quiet influence. Think of the Mafia, for example, though with more stealth. I'd suggest such posts as political lobbyists, clergy, and those "background" advisors to world leaders, diplomats and powerful business execs. 

Perhaps they might remain reclusive observers, in tight-knit groups, like sleeper cells; or maybe Kanye West is one gone rogue. Stands to reason. 

Speculating is so much fun. 

Maybe aliens would seek the capacity to study us, or our world; its not unreasonable to suggest they'd seek out certain fields of science or the study of our (rather sad, to be frank) history.

If an alien race were so smart as to successfully disguise their presence among us for any length of time, they would certainly be discerning enough to know that the best and easiest way of influencing great, enduring control over humanity --if that were a goal-- would be through religion.

Hmm,... the more you think about it...

Maybe we're just brainwashed aliens