"Anyway, heres the problem. In the solo you play one part way up at the 20th fret and I really can not do this on my acoustic smoothly. Any ideas as how to solve this?"

Since you're doing a new acoustic arrangement, why not just play the solo - or at least that section of the solo - an octave (or two!) lower? It may be interesting. Besides, acoustics can sound thin amd cheesy way up high on the E string anyway.


"Also I think theres an Eb chord in there as well. I thought about tuning down a half step and play an E but then Id have to play the solo even higher up the neck to get it in the right key and then Id run out of frets (only have 20)."

I'm fairly certain that every GNR song on all of their albums is tuned down a half step. IIRC, that song ends up with simple C, D and F chords (again, IIRC) that are much simpler to play with a down-tuned guitar (i.e. simpler than Cb, Db and Fb). As far as running out of frets, and assuming you don't drop an octave, why not bend the note?