I am a new millionaire @ 5m now. I started in December 2013, didn't do a lot of house farming (more like neighborhoods, some I still have and am improving with decorations). I bought premium characters and put them on tasks, usually shorter if I could handle it. I checked in a lot to clear buildings. A lot of friends could help, but you have to have enough buildings to clear otherwise the neighbors get frustrated with nothing to tap. I bought land - and have plenty of extra now (have it all), but don't have any of the aspirationals. I was surprised when I got my first million ( during Stonecutter's - where we could clear all buildings without interfering with friend visits). It happened fast. Now I am saving for the Sit and Spin, so still clear all buildings once a day and some of them throughout the day. I always leave something for neighbors to tap.
I can see why long-term tappers only visit once a day or less - but I'm not there yet. I still love the game and have lots of improvements to make in my town.