Trying to figure out if we had an additional 270 watts would batteries get charged faster, stay charged, etc.... can I run coffee maker, what is reason people add more watts? To get benefit do I need agm batteries??
OK, I've tried to address all your questions as simply as I can here below without burying you in figures and calculations.
Solar is best if you are off grid, or 'boondocking' a lot. If that is the case, then remember that no one ever complains of having too much solar.
One of the major benefits is that it is silent. You and those around you don't have to listen to the drone of a generator.
A coffee maker can take us much as 1800 watts. This will drain a pair of golf cart style batteries VERY quickly. TV and other electronics take very little. If all you are concerned about is running a coffee maker or a microwave occasionally, a generator is a cheaper way to go. Start it up, use your power hungry appliances, shut it off. Nothing prevents you from having both solar for 'everyday' use, and a generator for 'heavy duty' use.
If you have to run a forced air furnace a lot, the furnace fan will also consume a lot of power. If you are camping off grid a lot in less than full sun, you will want more solar. However, the price you were quoted for that additional 270 watt panel was exorbitant, to say the least. Shop around.
AGM batteries will only benefit you if you have to mount them INSIDE the coach somewhere, as they don't release gases.
If you are in RV parks with power a lot of the time, then just getting more batteries may give you enough power for a few days when you cannot plug in.
A 2000 watt inverter is enough to run a coffee maker or a microwave (though not at the same time) if the inverter is close to the batteries and wired with very heavy gauge wire.
FWIW, my wife and I camp off-grid (boondock) almost exclusively. We prefer the absolute quiet that it offers, so are loathe to use a generator at all. For that reason, I put 6 x 205 watt panels on the roof of our 30' travel trailer, and installed 6 golf cart batteries. We have enough solar so that we never run the generator, and we make liberal use of an 1800 watt Tassimo coffee maker, a 900 watt microwave, a 600 watt pop-up toaster, and occasionally a 1500 watt hot air corn popper and a small waffle iron. We both have laptop computers, and I never ever even think about watching the TV whenever we want to. Even if we use them all in a day, in full sun in Arizona in the winter the batteries are typically fully charged by early afternoon. And if we have rainy or cloudy days, we cut back, but still get a useful charge.
Here is what I installed, as well as my thinking on why we did it.
Hope this helps.