Your argument is backwards. You're asking us to explain how a travel agency "fits" into a certain shape of the Earth, yet you're the one who asserted that it does. The tone of your query (phrases like "if the Unipolar Model is to be taken as true, then how can a trip to the South Pole not only happen, but happen regularly") implies that you see this as a contradiction, but you've made no attempt to explain where the supposed issue lies.
To me, this sounds much like "I own a boat. How is that possible if the Earth is round? What gives?!"
Personally, I see nothing about organising trips to Antarctica that would contradict the monopole model, so I'm unable to assist with your question in its current form.