12 Volt - Direct Current (DC): 12 volt is the type of electricity you would find in an automobile. Your battery is the foundation for the 12 volt system in your RV. A fully charged battery will operate the 12 volt equipment (furnace, water heater, most lighting, range hood, monitor panel, roof vent fans, etc.) in your unit until the battery becomes discharged. The level of discharge for operation to cease will vary by each piece of equipment.
120 Volt - Alternating Current (AC): 120 volt is the same type of electricity you typically find in a home. Plugging your shoreline cord into a power source (campground or other appropriate receptacle) is the foundation for the 120 volt system in your unit (optional generators produce 120 volt electricity as well). Certain equipment (Roof Air Conditioner, microwave, most televisions, DVD players, etc.) in your RV can only operate from 120 volt electricity thus require the unit to be plugged in to a power source or a generator running.
Back up systems which are a part of your RV's electrical system.
Your unit is also equipped with a "Converter." When the shoreline cord is plugged into a compaground (or other appropriate receptacle), this device "Converts 120 volt electricity into 12 volt electrity. Most 12 volt equpment in your unit will operate from this power source, even if your battery is discharged. The "Converter" is also equipped with a "battery charger" which provides a "trickle charge" (slow, low amperage charging) to your battery as long as the shoreline is plugged into a power source.
Very Important! The battery in your RV is the foundation for the entire 12 volt system. Without a good battery, any 12 volt component in your RV can experience intermittent operational problems which can be extremely frustrating. This continuous discharging & charging is very hard on your battery. Be sure the water levels are checked at least monthly and the connections are kept clean and free of corrosion.
Yes, with a few exceptions. Most roofs utilize 3/8" plywood underlayment and are designed to be walked on. Please, always use caution when working on top of any RV.
Use automotive/marine grade "Non-abrasive" cleaners & waxes with a soft cloth. Avoid products with ammonia, caustic harsh cleaners and rubbing compounds. Avoid high-pressure washers, rotating brushes, etc. around graphics or painted areas. Do not "dry wipe" surfaces.
You should check your travel trailer brakes and have your wheel bearings packed every 8-10,000 miles - or - after 3 years.