As far as the batteries here's my take on it:
Unless you're going AGM, go with lower CCA starting/deep cycle batteries
I've had good luck with the
Cat 825 CCA batteries because the plates aren't as thin as on other batteries. They're also predictable, they don't short out and give off that sulfur smell. They just slowly get weaker and weaker and you have more than enough warning as to when to replace. Up here they have a full 3 year replacement warranty.
I'm pretty damn hard on batteries. Fridge runs all the time. I run an espar bunk/engine heating combo and don't idle my truck until it hits -25C. It's also pretty damn cold up here in case you haven't heard.