I've successfully learned Chinese fluently. Spending a year hanging out in a nicer part of the mainland while working through books and paying a teacher for 1-on-1 lessons a few days a week (~100CNY=$16/hr) should get you conversational. I strongly recommend considering Yunnan: good standard Mandarin, excellent weather, friendly people, good food, many points of interest. Americans can now get 10 year visas easily, though you have to exit the country every 90 days. This means you don't have to tie yourself to a formal school and its (slow, tedious) pace, plus gives you a reason to travel. Yunnan has great options for the border hops on the cheap: Myanmar and Vietnam (visa available in Kunming) and Laos (visa on arrival) are right next door, Cambodia, Sri Lanka, Bangladesh, India, Nepal, Thailand (visa on arrival) are also close.