If you do the #2 step, fencing out the mice, there is no need to buy a treadle feeder. 
If you only buy the chinese made grandpa feeder it won't stop the mice.  There are lots of negative reviews with pictures and videos on their Amazon page to claim otherwise.  The lid can be lifted by mice and without the hardware cloth enclosure the rodents will just eat during the day anyway.
To stop rodents you need either the exclusion method which is quite expensive or you need a proper ratproof feeder, heavy spring loaded door, narrow and distant treadle, and if you have to prop the feeder open you just as well save the money in my opinion.