All depends on if you want to. No real magic, just a bit of tinkering.
You will need a few specialty things, like an air compressor (if you choose to blow it out), a socket to get the plug out of the water heater, a suction kit for the water pump if your trailer doesn't have one, and a bypass kit for the water heater, but most likely there is one there.
I did mine this afternoon in about 3 hours including flushing the black and gray tanks. I use the fill with pink antifreeze and drain and blow out the antifreeze. I also drain and flush out the water heater. That way nothing is missed. Cost for mine is two gallons of antifreeze- about $7.
Lots of ways and opinions on how to do it.