Watch the I - IV - V Ionian online guitar lesson by Robbie Calvo from Modal Expose
I'm pretty sure this isn't the first time you've had a I - IV - V chord progression to solo over. What I'd like you to try if you would, is think in terms of this living on an album where you'd have to listen to it over and over again on the radio. Think about making a timeless musical statement instead of just a flurry of notes. Build a solo that has pace, dynamics and tasteful note choices. Of course make sure you resolve to a chord tone of A at the end too.
One of my favorite things to do when I start a solo is to introduce the chords by outlining them with chord tones. I also like to repeat ideas and melodic phrases to hook the listener. Of course my approach doesn't have to be yours and there are thousands of ways in which you could approach this piece.
Check out the video breakdown for some ideas and licks and then work on developing an Ionian solo that you really like too.