I'm currently bringing a near-empty Carrier back to the Bubble from Colonia. With 1,000t of tritium in the depot and around 1,200t in the hold, I knew I wouldn't have enough, so I've been stopping at all the Colonia Bridge megaships.
I'm doing OK. Many are in lockdown, but from those that are still open I can get around 40 to 100+ tons, and occasionally more. I've recently bought more than 3,000t from Cannon Complex station in Prua Phoe MI-B b17-5 (which is more than I've gotten from the megaships, there are now a few new full-size stations on the route too) - which is more than what I needed to get all the way back to the Bubble.
If you're travelling light, and stop to scavenge at every opportunity, you can make it.