i recently just solo quested a pally from 43 to 80 in about 2 weeks of semi casual yet exclusive play. played about 4 hours a night until 70 when i stepped up my game to do a level a day on average until 80. i used tourguide + tomtom and carbonite to fill in the gaps. tourguide ran out in howling fjord though. it was all in all pretty easy to do just took a little dedication, and was not as monotonous as instance boosting imo.