As for the letter, the simplest thing to do is just to share it as-is:
"When Doris was 12 she wrote in her diary, 'I sat behind Jim Whitecar in church today. Boy is he cute.' When they were teenagers Jim asked her to dance at a church party, and as Jim tells it they're still dancing. It was World War II. He joined the Army Air Corps. She would date and wait.
"They were married June 5, 1948 in Berkeley and repeated their vows a year later in the L.D.S. Temple in Salt Lake City, Utah. They celebrated their anniversary in St. Augustine, Florida with friends, and plan a trip to Fiji in September with family.
"San Franciscans, they have lived in Mountain View for 45 years, where they raised their children Krystyne, Jim and Steve. They have four grandchildren and three great-grandchildren."
For those readers reaching for their calculators, that's 60 years of marriage as of last month. (My anniversary, also early last month, was a mere seventh-year. The bigger the number, the more astounding the anniversary.)
I don't usually mention wedding anniversaries in this space, but there's no special reason why not — send them on in. If the number's big enough, I'll recount your story too.