He was diagnosed with non-small-cell adenocarcinoma, a much more treatable cancer that has responded to radiation and chemotherapy.
Now, 39 months since his diagnosis and taking the oral medication Tarceva, he has seen the metastases on his liver disappear and his cancer remains stable.
"I'm really fortunate," Stranathan said.
But he worries about Blume, whose cancer is faster growing and is more challenging to treat. She has three lesions on her brain that have been barraged with 15 rounds of radiation.
Steroids weaken her muscles, and double-strength radiation on her chest burned a hole in her esophagus. "I couldn't eat for weeks," Blume said. "That was the worst."
Now, the cancer has mutated and she has a large-cell lesion on her breast. "It's hard to stay positive," Blume said. "But every day I have Don, I feel pretty positive."
The drug Temodar, has at least kept her lungs stable since June.
When Blume visits California, Stranathan arranges for check-ups with his own oncologist and even a round of radiation at California clinic.
"He's very supportive and gives good back rubs," Blume said. "Don's a really good person, just a really nice guy."
Stranathan said Blume supports him with her smile and "bubbly personality."
"We have been seeing each other long distance for a year and have never had a disagreement," Stranathan said. "The fact is, we are going through this together and support each other. ... We laugh a lot."
Traveling can be stressful for both of them. Stranathan is sometimes short of breath and has stomach problems after long flights.
"But I don't want to complain," he said. "People in my condition aren't around anymore."
The couple hope that by telling their story they can create awareness for lung cancer, which kills 160,000 American a year, but gets comparatively fewer research dollars.
"I go to the grocery store and see support for other cancers, why not lung cancer?" Stranathan said.
The couple said patients are often stigmatized because of the disease's association with smoking, and yet many Americans who never smoked die from lung cancer.
The first thing people ask you is, 'Did you smoke?' ... saying you deserve it and did it to yourself," Stranathan said.
Blume said she quit smoking 15 year ago and Stranathan did the same 10 years ago.
"We need more screening," Blume said. "You go to the doctor and they do a mammogram as part of your yearly check-up. They do pap smears and prostate."
The online death notices of those who succumbed to lung cancer are a grim reminder of their fragile romance when they revisit the Web community Inspire.
"We meet good friends, but it's hard," Stranathan said. "A normal person loses a friend every once in a while. We lose friends every day."
In the meantime, both try to eat a healthy diet and take their supplements and vitamins.
During this current vacation, they will pop down to Los Angeles to see Stranathan's son, then maybe go to Yosemite. They plan to attend the wedding of Blume's son in Las Vegas. In February, they hope to go to Hawaii.
Blume is scheduled for stereotactic radiation for the brain nodules when she returns to New York in October. "I admire her strength," Stranathan said. "She has been through a lot in such a short time."
But he has faced his fears and put his "house in order," even prepaying his cremation.
But both say it's their love that has kept them alive.
"It's critical to have things like that to keep you positive," Stranathan said. "Any cancer survivor has to have short-term goals, so I look forward to being with Penny. We never know what will happen to either one of us."