I lose bodyfat VERY quickly with no cardio at all. I force myself to gain weight and actually am kind of sick of doing that because there comes a point when the weight is just pure fat. You really cannot rush a growing muscle.
What is your opinion on a bulk phase for 4 weeks followed by a cut phase and so on in the offseason?
I've given this some thought. (I've had to... It's been a while since the days I trained 'natural', and most of the guys I give advice to are no strangers to the juice.) I think that the best way to go about achieving your post-contest goals would be to go on a rather mild, yet prolonged 'bulking' phase. The objective here would be to pack on lean mass over the course of several months -- even up to a year, if you see fit.
Actually, if you train hard and eat right, it may be a while before you have to diet... If I were you, my 'goal' would be to gain a pound of muscle a week. (An almost impossible task for most naturals... This would be 55 pounds in a year!) It's a very lofty goal -- probably impossible -- and if not impossible, certainly unsustainable. But I need to make an important point,
to gain one pound of muscle per week, you only need to consume about 100 calories over maintainence per day. 5000-6000 calorie diets are flat-out counterproductive for healthy (read: 'not dangerously underweight') natural bodybuilders; they're only of real use to 110-pound hardgainers looking for fast mass, football linebackers, and steroid users with superhuman protein synthesis rates...
There is a certain level of calories that are required to maintain a person's bodyweight. To gain muscle with minimal fat, assuming your training is in order, you simply need to consume
slightly more calories than your maintenance level. To lose weight, slightly less. Hormones, hypo/hyper-thyroidism, and
extremely high-intensity/high-volume training can skew the equasion a bit, but that shouldn't be an issue for you.
Bulking the way most novice bodybuilders bulk is, in my opinion, a less-than-optimal way to go about gaining muscle. Eat clean, don't eat too much, and you'll make steady lean gains over time...