Last fall we used the Premier through the freezing nights and I started using antifreeze. It was pretty straightforward but I decided to buy an air compressor so that I wouldn't need to keep buying antifreeze every weekend.
It takes a little more time to pack up at the end of the weekend because I have to blow out the pipes before we leave, but it really doesn't take a lot of time. I only use a little antifreeze in the p-traps.
I follow the instructions in the Keystone service videos. I have a link on my webpage:
Keystone How To Winterize