Hi Papa Rich,

It sounds like your biggest struggle is with keeping up with tempo of the song. I say this because you mention you have trouble playing with a backing track. It takes a lot of time to play a song beat for beat. It sounds like you're doing all the right things though if you feel you can play a song without the backing track. I suggest using a metronome to keep the beat of the song, if you haven't tried that already. Remember, we have a metronome here: https://www.guitartricks.com/metronome.php

As far as improvising goes, that also takes a bit of time and training your ear and studying scales. Try this lesson, it might help: https://www.guitartricks.com/tutorial.php?input=1591

I hope this helps!