When I wired my friend's powerwagon I ran the 2awg cables under the truck in split loom, with lots of cable clamps and Zip ties to secure them tightly.
I'd not do the Inverter/charger thing unless towing a travel trailer, and the vehicle's voltage regulator was a 13.7v clown.
The alternator is so capable at bulk charging, I choose to harvest All I can from it. I'm not much fussed if this shortens its life as I can swap it out in 15 minutes and it is just a reman with a lifetime warranty, but if it was a PITA to swap and 300$ I would think differently about maxing it out often.