Ironically, I'm not a natural exerciser and I struggle to do big blocks in the day...
Teetime - I would say that amount of golf is perfectly aerobic. The walking combined with swinging a weight at speed is excellent. Add in the Zumba and you're golden. :-)
I would focus on recovery and muscle balance. So with golf there is always a rotation the same way, do your swing (slowly, under control, no weight) and see if you have the same degree of rotation the other way!
I would think about rolling or massaging your calves, just to condition the muscles you're using a lot. Shoulder rolls, basic stretching and little things like that, when you're sitting and have a moment. There is a lot of random stuff you can do, like incline pressups against a wall, sit to stands, which are squats off the sofa and very useful. Try standing on one leg whilst you brush your teeth, don't fall over tho!
If anyone of you use your hands on your knees to get up off the sofa, the "sit to stand" is a good one to try...
My Mum has had both a shoulder and ankle replacement this year, keeping good leg strength would have helped her hugely.
My favourite thing at the moment is #5minuteflow. It's just a series of movements tied to a cue, like getting out of bed.
Google this and you'll see a nice, fit guy demo it! His range-of-movement is excellent, but start at the level you're at currently and explore. Hope this helps!
I would normally use lots of clicky links but I think it's not in the spirit of the forum rules here and I don't want to get into trouble.