Dutch men Sport has the right idea.
We took Costco brand toilet paper to Alaska last year because it came wrapped in packages of 6. They were jumbo rolls. I couldn't even get them into the holder when new.Once used for a few days, then the roll was small enough to fit.
Make sure you squeeze the roll out of round a bit before installing, or the roll will unroll onto the floor:S.
When we got home I compared the Costco brand to our regular brand and there was about 1/2" difference in diameter. We have decided to buy TP on the road rather than take 5 month supply with us next extended trip.