I used to work at a RV dealer in the parts dept. The service techs always came to me when they needed pink juice for winterizing a trailer. 2 jugs is about what they were able to get the job done with.
But keep in mind, using too much pink stuff is far better than using too little.
Don't forget the city water connection water line or the 'P' traps under the sinks and tub.
With that in mind, I usually use 3 or 4 jugs. A gallon of pink juice is a lot cheaper than fixing a split pipe in the spring.
FAA A&P mechanic, ex-RV dealer parts dept
Retired B-52 Gunner/Flight Examiner, B-52 Crew Chief
2016 Jayco Eagle HT 29.5 FBDS w/ 15,000 BTU AC, 50 amp service, upgraded counter top, thermal pane windows, elec. stab jacks, outside grill, backup camera and MORryde pin box.
2011 GMC 2500HD DURAMAX/ ALLISON