mirax, thanks! I appreciate the sentiments of good luck! I'm a past Masters-level competitive swimmer who's gone very, very soft. At 44, I'm also discovering that a body that's been in motion, desperately wants to remain in motion, and will send you all sorts of messages.

I can hold my weight at the "healthy" number by watching what I eat ... but my LDL goes through the roof unless I exercise. I got slapped in the face with a 205 LDL/295 total cholesterol about 3 weeks ago - first time I've ever failed the ratio. And my left shoulder is my bellwether of fitness - it acts up when a) I am stressed, b) when my neck is out of line and it's time to visit the chiro, and now c), when my back and abs are too weak to keep it in proper alignment.
So ... I am sneaking up on fitness without getting my brain into it too much. I'm just running/walking on the treadmill, and last week I took my first deep-water aerobics class. It's accelerated my weight loss a bit, plus I feel "firmer" in the softer spots. When my shoulder gets back to not hurting, then I will go back to lap swimming and resistance bands - just very, very carefully this time!
I honestly don't know where I'll end up. In the best shape of my life (junior year of HS), I weighed 150, but could bench 165 and was 9-10% body fat. Ten years later, I was in the 140's and "skinny fat" at close to 30%. These days, my goals are more around functional fitness ... but I won't rule out short-course Nationals for next year, either!
To your original post of "where to stop" - I guess it's where you find your balance of doing things at a level that you can do them forever. The scale's a dependent variable ... not a result in and of itself.