I have no idea what your coach batteries capacity is!
I was speaking in generalities.
You would need to look at the batteries and write down the manufacturer and model number and do some research online.
A 1000 Watt pure sine inverter is a perfect size for our needs (less high draw items like: Microwave, Air Conditioner, Heaters, Irons, Coffee Maker, blenders, Hair dryers, curling irons, Toasters, etc.) It will power your computer, TV sound system; charge phones and other battery powered appliances that have AC chargers like laptops and do it all pretty much at the same time for as long as your batteries last.
The article I sent you about battery capacity explains how long that will be based on amp draw over time.
If you use the inverter at its max draw (84 amps) and "normal" Camper usage, say an average of 10 amps (fridge, lights, Propane detector, and water pump), and your battery bank turns out to be, say, 160 amp hours; you should get about 120 minutes out of your house batteries before they needs a total recharge. Less amp usage will not only give you longer battery life, but MUCH longer battery life since charge consumption is not linear. If you look at the chart in the previous post you will see that your capacity drops pretty fast the more amps you demand at once.
For example, if you have a 100 amp hour battery bank; it is way better to pull out 10 amps for 10 hours that to try and get 100 amps for 1 hour. Due to the capacity reduction of about 50% (to the inability of the battery plates to release electrons at that rate) you would only get about 30 minutes of battery life at a 100 amp draw.