The only "regular" toilet paper that I wouldn't use in an RV is Northern. My S&B pipes get tree roots. When I used Northern, the pipes would clog every one to two years without fail. After snaking, there would always be a small amount of roots and a lot of TP. Then I tried other brands (Kirkland, Charmin, Angel Soft, etc.) and have gone almost 4 years without any trouble at all. When I did the glass of water test, I found that Northern did not disintegrate like the others. All the others fall apart very easily and don't get tangled up in the roots.
