60lbs is A LOT of mass you need to gain to your 140lb frame. How many months are you giving yourself to accomplish this? You better eat alot of carbs/calories and protein shakes. Forget the word "lean" for the next several months meaning cardio and core should not be the main of your focus. Gaining the amount of muscle mass you want to put on your frame is going to give you weight on your mid section so if you notice a bit of a gut coming on, don't worry about it. You can burn that off once you get done with bulking. If some cardio is a must for you, I'd do mild pace walk on an incline on a threadmill or stair master. Alot of cardio will eat away at the mass you are trying to build so no heavy cardio training while on bulking. That would defeat alot of your purpose. EAT EAT EAT!!!!
THIS