your profile says 71 GT, so lets go with that. Dry weight = 3460 pounds and hitch weight = 420 pounds. These numbers are from the factory with no additional options, no water in the tank, no propane in the tanks, no shoes under the bed or beer in the fridge. Your numbers will always be higher.
No 220 volt system should be present. The shore power plug is a 30 amp 120 volt RV style. It may look like the one for your dryer but it is not. Do not plug it into that outlet! The 120 volt shore power will run the Air Conditioner (an option), the 12 volt
power converter (also charges the battery), the refrigerator (when on electric setting) and all the 120 volt outlets in the trailer.
When running the refrigerator on propane, it heats the ammonia in the coils and that makes it cold. I think it is magic, but it works. There are different models of refrigerators, do you know what yours is?