Travis Morgan has an adventure outside of Skartaris in the Mike Grell story from Warlord 6 (April/May 1977).
Although we saw Morgan on the surface at the end of the previous issue, it was hard to tell exactly where he was. The beginning of this issue makes it clear that he is at the ruins of Machu Picchu, in Peru. He stumbles into the tent of archaeologist Mariah Romanova, and collapses. When he wakes, he learns a lot of things. Firstly, that eight years have passed since he entered Skartaris, even though he knows he has not experienced that much time. Mariah is Russian, but part of a larger, international expedition at the Incan ruins.
They have discovered an ancient temple to a cat demon, and suspect it is Atlantean. Travis is able to confirm the Atlantean part, but informs them that the inscription indicates a tomb, not a temple. I should also mention that Mariah is none too keen on Morgan, after he admits he was shot down during a spy flight against her country. The archaeologists decide to open the tomb, and find what they believe to be a giant statue of the cat demon.
They also get around to mentioning to Morgan that they contacted the US military after seeing his dog tags. Morgan is furious. The army will consider him a deserter at best, more likely a defector. Indeed, a squad show up to arrest him, as well as the archaologists, who they do not trust, because of Mariah. The leader of the squad is not named in the story, but will be called Stryker when he returns down the road. Mariah helps Morgan fight off the murderous operatives, and Stryker gets knocked out.
Mind you, they get a bit of help in this from the cat monster, who comes to life when sunlight reaches him. Morgan manages to kill it as well.
At the end, Morgan convinces Mariah to return with him to Skartaris, as her life on the surface world will now be in danger, and her skills could help solve some of the ancient riddles. They take the subway car back to where it started, but Tara is nowhere to be found. Although only a day has passed for Morgan, the helmet he left behind is now covered in cobwebs. How long has he been gone in Skartaris time?