The easiest thing to play is some kind of C minor scale...most likely Bb Major (aka C dorian) for the first 8 bars of the tune.
Of course, there are more interesting things to play. I like to think primarily
in C minor. I alter the scale I am using depending on the chord I am playing it over. This way, I don't have to worry about modes, or scale fingerings. I actively track the chords and the prominant notes- which change and which stay the same.
The downside is that you must
know your chords like the back of your hands.
In other words, I think Bb major for the C minor chord. I adjust the scale by switching Ab for A during the Fm7 chord and Dm7(b5) chord. The G7(#9) causes me to think about Bb major scale with a B natural and C# added to it (major third and b5, respectively).