I am in Virginia, so all I have to offer you are a few basics. There are a lot of resources available on the web as well.
You have a travel trailer, so while you are fully hooked up to your tow vehicle and under way your trailer battery (the power supply for your 12V DC system - 12 Volts, Direct Current) should charge from the alternator in your truck. This is good to know because if you are in a campground and the power goes out or you are camping without hook ups and need to charge your batteries, your tow vehicle can do this.
What's the relationship between Watts (power), Volts (potential difference) and Amps (current)? W=VA - so, 120V x 30A = 3,600W - which comes in handy if you are thinking about buying a generator as they are rated in Watts! Once you get to the campground and plug in to their 30A (or 50A) service, your charger/converter should keep your battery charged and convert the 110V/120V (both numbers are used for Alternating Current or AC systems) electricity from the 30A (or 50A) service to power your 12V system.
Some appliances are powered by your 12V system and some are powered by your 30A/110V. All outlets are powered by the 30A/110V system. If you have an RV fridge, it may be single source, 2-way (propane or 12V) or 3-way (AC, propane or 12V) and you'll have to make the choice about how to power it. I use AC as the campground costs cover that! Your microwave and air conditioner are powered by the AC or campground power. Your camper lights are likely powered by the 12V system and will run while plugged in or off of your battery. Your hot water heater may run off of AC or propane with you making that choice. If you are boondocking and run it off of propane, the ignitor will use your 12V system to light it each time, so it won't work without a charge on your battery. Your furnace likely runs off propane but will need the 12V system to ignite it as well.
Things like the AC and the microwave and hair driers and hot plates take a lot of current and you are limited to 30A in your camper - really only 25A or so after standard drains like your monitors and alarms are subtracted. Basically, anything that heats or cools will draw a lot of current. So, before you pop your popcorn in the microwave, turn off your AC. Otherwise, you may try to draw too much current and you may trip a breaker.
If you buy a generator and you want it to serve as your "campground power" and you want it to run your camper just like if you were hooked up to 30A, you need to buy at least a 4000W generator that can continuously provide 3600W. The power rating on the generators is typically peak power and that level can't be maintained. You can also buy 2 2000W ones and run them together to give 4000W if you buy the right kind.
I am re-reading your post to see what I missed - DC current is the same all of the time - "direct current" - the Current vs Time graph looks like this:
-----------------------------------
AC current alternates between -30A and +30A and the graph looks like a sine wave or kind of like this:
/\ /\ /\ /\ /\ /\
/ \ / \/ \ / \/ \ / \
An inverter takes a 12V current and flips part of it to negative and that graph looks like this:
----____----____----____----____
Sensitive electronics cannot handle this sort of thing but some can. There are "sine wave inverters" that produce a graph that looks more like a sine way and that is what is needed for some 110V devices to work properly.
A converter takes the sine way current and flattens it so things expecting the same current all of the time get it.
I hope this helps! If I confused it at any point or you have more questions, please message me and I will give it another shot!