What do you recommend? Trunk Battery, like to put a inline fuse. what size?

What do you recommend?
I am putting my battery in the trunk. I want to put a inline fuse or circuit breaker off the battery in the back. Most likely going to use a circuit breaker. This way I do not have to worry about a fuse.
What amperage should I use?
I did go with a 100 alternator if that matters.
Thanks for the help.