Lovely story. Wife and I are in exactly the same position with our cottage on the shores of lake Huron. I had a spinal decompression and fusion 4 years ago and am on the waiting list for a hip replacement. Athelene just had a knee replacement 4 weeks ago. Our three children all have busy lives in different cities and are visiting the cottage less and less. Even the grandchildren, growing into teenage years, are so busy in the summer that it is difficult for them to find time to visit.  Maintenance is slowly falling behind and the cedar hedge there is tall and wide enough that I almost need a helicopter to trim it. 
But we keep putting off the decision. Everything really depends on the results of the surgery. If we recover enough to keep up with the maintenance we will probably keep it a few more years. If not, we will sell. I agree with the author that the cottage means a great more to us than to the children. But one weekend with the grandchildren is enough to change our minds.