MaryEileen,
Have you dry camped yet in your new rig?
If yes, how did the battery hold up with no inverter?
I use an average of 80 kWh electricity per month and many folks use 10 times that, so it is hard to guesstimate without your participation in a Q&A session.
I can tell you that a slow cooker uses more power than you may think. 150 watts per hour for five hours is 750 watt hours. It equals the allowable discharge in one group 27 battery, but when driving this is a non issue. A few hours of television depends on the television. Some use a LOT more power than others.
How long at a stretch you camp is crucial as is how for how long a time you drive between campsites.
How many lights do you use at a time and for how long?
If you camp long enough to need a generator the charger in your rig has to jam as much as possible back into the batteries in the time you allow generator run time.
So if you can provide answers or guesses to the above questions it will be a starting point.