Kyroru
I think the next reality Carl should go to is the DC universe, but not just any DC universe, but the Flashpoint Paradox. He could enter the altered timeline first where the Atlanteans and the Amazon Women are at war with each other, and probably loot some important items like Nth metal and such. And I think that Lois Lane would be a good choice to bring back to his reality, ‘if’ they do get interested with one another. Also, when Carl decides to go back to the DC Flashpoint universe, he won’t be in the altered timeline but in the fixed timeline after Flash fixed his mistake. And no one but the Flash will remember Carl being there, but it’s possible that Flash will tell Batman (Bruce) about Carl. And here’s the kicker, a Lois Lane will still exist in the fixed timeline while the Lois Lane with Carl will still exist because she was outside of the universe before Flash undo the altered timeline. Making Lois with Carl… A. Living. Paradox. (And I’m not sure how the whole ’world hopping can help you avoid being affected/erased by someone else’s time travel’ thing works, but that’s just seem like an interesting way to counter time travelers.)