I'm not the best qualified to answer but will give you some of my thoughts:
I'd start with an A scale.
Then recognize the chorus of A G D and make it a myxo.
Then realize that it has a C#7 vs the C#m in standard A so I'd be sure to put some emphasis the B of that (ii in A) as well as the F (the IV of C#7).
Then I'd recognize the D#7dim and chalk it up to an accent of D7 and ignore it
So I'd by playing the following notes
A B C# D E F F# G A
What is that an A mixo plus an F?
(this is how my mind works so freakin' analytically that it stiffles my ability too often to let go and just solo !)