On my second Sandpiper I ordered the heated tanks, however it doesn't help much if you are dry camping. If not, the 12v system should heat them without problems and the furnace should provide enough heat in the belly to keep it form freezing. That being said, you have to have 15, 30 or 50 amp. As far as outside pipes? If you are talking water hoses, some use electric heated pipe tape and wrap their water hose and spigot all the way to the ground and then wrap insulation around it. I hope you understand your question.
2012 Sandpiper 365SAQ weighing @ 15k, Onan, 2nd air, slide toppers, TST
2013 F350 6.7L Lariat 4x4 CC DRW,Viair 1007, Ride-Rites, Edge CTS, B&W
2001 Chevy 3500CC DRW 4x4, 8.1L, 4.10 gears w/ Detroit TrueTrac
2001 Ford Excursion Limited 4x4 7.3L,V/B Spring Mod, ProComps, Hellwig Swaybar, & other 'Necessities'