I went from 235 to 185, in a year and change, no one really noticed until I broke 200. But I was lazy and disabled, I had to push thru the pain to get in shape. The eliptical walker burns about double what the treadmill does, Having owned a gym I knew what to do, just seemed like a daunting task. I started with 15 minutes on the eliptical and worked up to 40. Now I could go as log as I want but 1/2 hour 5 times or even 4, is enough to maintain.
Also hit the weights, 4 sets of bench and flies for chest, curls forBiceps, triceops pulldowns and kickbacks, for triceps, dumbell and machine curls and cable puldowns, No shoulder other than once is a while and the legs get hit by the eliptical.
Once you loose the weight you should re proportion the body so you make the most out of what you have.
The first 6 months really is all cardio,get that weight off, the weights are really a waste of time untill you loose the fat, but a little weight training is ok, as muscle is needed to burn fat. concentrate on the large muscles like chest back shoulders, "if you can", some guys have a specific injury, like "back" that makes it hard to work around. The idea is to make sure you are supported "like sitting" when you work those areas.
Machines are better as you get older, as free weights can move off center and strain a bad back or shoulder.
Same with legs, after 40 you don't want to injure a knee, so just extensions and leg curls, are enough if you are doing cardio.
Cables are great also. I am turning 65 and look better than I did "body wise" 15 years ago. I had big muscles, but a lot of body fat, my blood preassure is normal and also my cohlesterol, with no pills. Cut out the booze to weekends only and wine instead of vodka, and eat healthy, we all know what we should eat we just are to lazy or in a hurry to do it.
My wife is into it also so it's easier. That's my take on it, I said I would get back into the shape I was when I moved to FL, that was almost 20 years ago.
You have to stick to it, there are months where not much happens, I strive for 2000 calories a week on the cardio that's 5 days at 400 per day. It takes 1/2 hour. If I did nothing else that would have taken off the weight in about a year and a few months.