Thanks everyone for the helpful comments! You all inspire me on multiple fronts: much more attention to diet and portion size, more vigorous aerobic stuff, and consistency with the weight training.
With respect to Mark Lauren's "You Are Your Own Gym," and Leonidas's comments, the book is not only clear about the need for proper form but is supported by a superb free app (for both Apple devices and Android) that has workouts ranging from basic to very advanced and links to careful reviews of form for each exercise. Given his background - THE training program designer for Navy SEALS - it's well worth looking at, IMHO. My conclusion though after working with it regularly for a few months is that it's probably much easier to transition to for those already used to using free weights properly (i.e. with good instruction from a trainer and a few years of use), not only because of the importance of precise form but also because starting off with your full bodyweight as your only resistance training option is so hard for many exercises that it could cause all but the most motivated folks to quit.
Thanks again for all the great sharing of hard-won wisdom from experience. I really appreciate it.