While I don't really see a lot of interplanetary or interdimensional travel happening in the Athanor campaign, Blair at Planet Algol asked about including a gate to Athanor in his campaign. My answer was an unqualified yes -- I don't see Athanor as exclusively mine. I put the campaign development up for people to see and use as they want because I feel like that's part of the essence of the hobby. It reminds me of something I read in the first issue of Fight On!
In his editorial "In the Time of the Broken Kingdom," Ignatius Umlaut recounts an article in New West magazine in 1980 that describes the hobby from an outsider's perspective, with gamers hopping from campaign to campaign and tributes and crossovers to other DMs games happening, and PCs going from table to table (and from system to system!) on a regular basis. Umlaut notes that "people played in different games and worlds, of course, but there was still a sense that we were all part of one big fantasy multiverse," and that in the original New West article, the author "also describes players mailing their characters halfway across the country to visit or defend or attack other worlds, and wonders if her son’s character surviving a run in Greg Stafford’s Snake Pipe Hollow might find himself mailed away to defend Mistigar."
When I was a lad, we often moved characters from campaign to campaign (or even from system to system) with little sense that this was going to be considered wrong. It was how things were done. Now, people treat campaigns and systems as sacrosanct, and that seems, if not a loss to the community, a change in how we conceive of the openness and options at the table.