Hi Igy, we're not ignoring you. Most of us usually post on the weekend or Mondays (like mo'pak, who's on the wrong side of the international date line). I'm 66, ran a 20:12 5K in April, and have been trying to rebuild from a bad case of runner's knee since the end of April. I have more training philosophy than specific training recommendations.
It is my impression that for those of us who still are hanging in at this age, training becomes progressively more of an individualized structure dictated by our particular strengths and weaknesses. Some of us do better with a shorter higher intensity program, some with a long low intensity program, and others with their own optimal mix of both.
At this age the fundamental training principal is don't get injured. Simply getting a long block of uninterrupted training of almost any kind is the best thing you can do. This involves two elements that I rarely follow, be patient and be conservative in your training plan and goals.
My training usually is structured around our local Fall XC series which has 6-8 races from 5K to 8K, spread from mid-August to early November. When healthy I was running 6-7 days a week for 45-55 mpw. I am rethinking my training as I try to get healthy again. I was not doing much cross-training to build strength. I do row on a rowing machine for 20 minutes almost every day before running, which gives me a little aerobic work, but which I think mainly provides some core strength and good range of motion work for my legs. I think leg strength exercises become progressively more important for speed and injury prevention the older we get. I currently am doing a routine of lunges and squats to rebuild some strength that I had lost, and that lost strength probably was the primary cause of my knee injury. At our age I don't think you can maintain adequate leg strength anymore with just running. At least, I can't.
As far as specific workouts go, I think you have to experiment with how intensely you want to run them, and how quickly you recover from them. Sometimes I can manage 3 workouts per week, sometimes 2 seems challenging. Here is my current "healthy" training plan I am working back towards, I am going try a harder hard days, easier easy days approach.
M- 8 miles moderate pace with 16x :30 hard/:30 easy up a 2 mi road that climbs 800', starting 1.5 miles into the run.
T- 6 miles walking at 15:00/mi pace.
W- 12 miles, 2mi warm up, then 5x hard mile/ easy mile (this is the workout that I injured my knee on)
Th- 6 miles walking at 15:00/mi pace
F- 8 miles easy, or whatever I feel like doing if the 8 seems like too much
Sa- 11 mile progressive trail run - I run this with my son and daughter-in-law and hang on until they drop me. Two years ago I was fit enough to hang with my d-in-law (a high 17s 5Ker) for the whole run. Before my knee injury (and after a Dec. calf injury at XC Nats) I was hanging on for 6-8 miles and then getting steadily dropped. I really don't care if this run is optimal training or not. It is quality time with my kids.
Su- 6 miles walking at 15:00/mi pace or off depending on fatigue.
I hope this is some food for thought for you, and I am sure that some others will chime in soon with other good thoughts for you to consider.
Best of luck and enjoy the effort!