I know you already have a lot of long answers, but it's hard to keep it short. I have a few back problems, but mostly I have trouble doing aerobic workouts cause my feet are really bad. I finally had reconstructive surgery after 10 years of agony. I've always been one for keeping it simple. It's about metabolism and calories in and out. There are ways to increase your basic metabolism (i.e. how much you're burning when you're doing nothing) drink water, eat more protein and fiber etc., but the major one is build muscle. "They" say that women can lose upto 1% of muscle mass per year after the age of 30. I do a body for life workout, lifting weights for 1 1/2 hours twice a week. I try to eat healthy, but I also want to live. I have a 2 yr old and a 7 mth old and I have lost all the weight from the last one plus some. I am the same weight as in college. If you don't know how to lift correctly get a trainer for a couple of sessions it is important to do it right otherwise you are just wasting your time. My aerobic workouts that I have been able to do have been interval training on the bike for 20 mins (this is included in the 1 1/2 hours.
If you want any information on interval training and why it's better for speeding up your metabolism or on a lifting regime that would work for you please let me know. I've been lifting for almost 20 years and I would definitely not consider myself bulky. Hope this helps.