if it started theres no problem with the starter or cables. and if the cables were removed and it stayed running, the alternator is fine, which leads back to the battery which you had to jump in the first place.
its been sitting that long my suspicion would be the rough idle is just some bad fuel that was left in the system that needs to get burned out, being returnless it may take a little bit for fresh stuff to get there. a new fuel filter wouldnt hurt either.
as far as the popping in the speakers, its usually from a bad ground from the engine to body. check your ground points and clean them.