Alicornutopia

Since that's a fairly useless form of travel, they used it by accident and are now trying to get home, presumably. The only reason not to keep jumping would be to deal with immediate needs (food, sleep, healing), deal with per-world complications, or look for a more controllable transportation system. —That seems compatible with my “meeting in a wilderness” idea, except for Bob to be happy at the end he needs to be in his original world or they need to find something. I can think of some things to do with the former (world-specific complication to reactivating the device, sharing useful magic to take away). If you're interested in this situation and sandboxing with someone who's never done it before, anyway.

It wasn't an accident. In their story they are looking for souvenirs to complete a quest; they don't control where it goes but have a reasonable expectation that it is going Correctly. I can hijack the Correctness of the device for sandbox purposes just fine, is all.

I sandbox with people who haven't sandboxed before all the time :) IM me.

Perhaps Exaltation would have interesting wishes at a 'pool?

There could be ambassadors and diplomats to other kinds of aliens, such as hivers.

First contact with hivers in Quinn's setting would be interesting but wouldn't involve Quinn-the-character.

Supposing the emlood make first contact with some new aliens, so the humans negotiate access to them via the emlood? Might be too indirect unless you pile several ambassadors and diplomats into the same room.

Doesn't work; the Species Of Diplomatic Hubness is the Tharansi and if the emlood find a new species the Tharansi will talk to them and the humans will talk to the Tharansi, not the emlood, about them.