First, I wish to comment on bulking and cutting at the same time. You can't. When you're trying to "lean out," you can't simultaneously bulk up. So, the question becomes two separate issues, bulking or cutting. Since you indicate a degree of frustration about still being a size two, I will address that.
A ten-pound weight gain over the last five years is really not so bad, especially since you were under 100 lbs. to begin with. So don't be too discouraged. Progress means you're moving forward and even if it may appear slow, it is better than being stagnant.
To put on lean mass, you must train at a higher intensity (i.e. heavier weight). This requires more time off from your workouts to enable longer recovery periods. Therefore, a 5-day a week routine could be 3 days on 1 day off, 2 days on, 1 day off. Another option would be 2 days on, 1 day off throughout the week.
When training is at a high intensity or heavy workload, then having more time off to recover from workouts allows the muscle to progressively respond to heavier loads and higher volumes, thereby enhancing its growth.
Because of the higher workload, perform fewer reps per set. Try to aim for six to eight reps per set on compound exercises such as the bench press, squat, leg press, bent over rows or T-bar rows, and the incline barbell press. Understand that you're sixth, seventh, or eighth rep should not feel anything like the first. It should be much more dificult. Always reach for that extra five pounds. For example, say you're squeezing out eight reps with 95 lbs. on the bench press. Training this way will not allow you to "coast" during your sessions.
I strongly recommend tracking your progress in a logbook.
You won't be able to train everyday with this kind of intensity. The demand of the workout just won't allow it. So train instinctively. On days you can train heavier, do so. On days when you're more tired or under greater stress, train with slightly higher repetitions, eight to ten. This is what I call a "train don't strain day." In other words, you're not straining to get up the last rep or two, like you would on your heavier weight days.
I don't believe it is necessary to train lower body more than twice per week. And please split your upper body workouts into at least two separate sessions. To train your chest, shoulders, triceps, biceps, forearms, and back all in one day is just too much, especially if your goal is to put on mass.
Concerning cardio workouts: I suggest cutting back the intensity and the duration. Doing excessive amounts of cardio works against mass building. Keep your power walking, especially if you like it, but don't go longer than an hour. For the remaining cardio workouts I suggest 25 to 30 minutes of something that keeps your target heart rate closer to 65% of your theoretical maximum. You'll utilize more fat for energy without the risk of catabolizing muscle protein.
Whenever you're attempting to increase lean mass, caloric intake should be higher than normal, especially in the macronutrient protein. Eating more of the right food tells the body plenty of nutrients are available to supply the demand exercise is placing on all physiological functions. Allowing yourself to be a "little fat" for this bulking phase is optimal. This is why bulking and cutting are in direct opposition to each other.
Dietary supplements are very important to any type of training program, especially if you're trying to increase muscle mass. The few I mention here have valid scientific research to support their effectiveness in assisting the body to maintain and/or build muscle proteins with the stimulus of exercise.
There are a host of other dietary supplements beneficial to a lean mass building regimen such as antioxidants, recovery supplements, and other specialty compounds. They are too numerous to be addressed here.
I hope this information has been helpful and useful. Again, I wish to reiterate the importance of tracking your progress in a logbook. Nothing else liberates the pro's and con's of a training regimen than seeing it in black and white.
Till next time, "Train Smart, Eat Healthy, and Mediate Daily!"
Samantha Lynn is a world champion natural bodybuilder with a Master's degree in Exercise Physiology. She's a member of the American College of Sports Medicine and is a Certified Strength and Conditioning Specialist. She's been involved in the bodybuilding industry for nearly two decades and consults with athletes of all levels concerning their lifestyle management in their sport. You can email questions about training, dietary supplements, contest preparation or anything else related to health and wellness, to Samantha at firstname.lastname@example.org. Check out her websites at Teammuscle.com and Samanthalynn.com