Congrats on working through the song! Indeed, it is a bit of a tricky one - so you should feel very good about all that hard work coming together!

As for the key --- you've discovered we made a mistake in the notation! I've alerted our transcribing dept. to correct it -- that key signature should be D major (2 sharps).

Now, as far as soloing a bit on top of this tune can also be a bit tricky, since you're thinking D major -- BUT, the song actually flows back and forth between a D major and D minor sound!! This is actually very common in blues - and is also used alot in country and rock.

Notice how the song has a major sound on the G and A chords, and most of the D chord, but there are times on the D chord when we are switching to the minor third (that bluesy bend 6th fret of the low string!) -- that gives it a minor sound.

So, I think you could use D major over the G and A chords, but experiment with using both D major and D minor pentatonic over the D chord. Depending on what is happening with the D chord at any given time, it may or may not sound good! It's a bit of trial and error, but you should be able to tell with your ear when it locks in and sounds great!

Hope this helps, let me know how it goes!

Mike