Welcome aboard.  41 here.  I picked it up again a few months ago.  I made a related post the other day and two things happened: (1) Christopher responded with some good links of his lessons, which I felt helped a lot, but there's still the "but, wait.... I still don't understand" feeling, because I think it's beyond what we can really understand now.  Seeing more math created by the fretboard will help to capture that knowledge. (2) ScubaCPA said that the book No Bull Music Theory For Guitarists really helped and reading the reviewsd seems to support that    

Bottom line you can watch the theory vids and try to think about how the fretboard spots are calculated and write some notes or draw to just help make it click, but having the guitar in hand would be perfect just for the sake of following by finger