Playing with just a few villages, it is definitely possible. It's a bit of pain because you don't have an easy way to switch between villages (in desktop view), access to the incoming tagging feature, access to the incomings overview, nor do you have ability to use a lot of the other convenient overview; however, for a small account with a few villages, it is possible. Once you get over a few villages (5 or more), I consider premium essential. It is definitely possible to play without it, but it would be very difficult and far more time consuming. Once you get over 25 villages, is definitely necessary so you can keep buildings and troops queued and properly time attacks/ops.