if you are going to bring power into the cab and feel the need to have a big power block in there then think about the possibility of running a mega fuse near the battery, to start the circuit with a fuse rather than run a large cable through the firewall or floor with no circuit protection until further down the circuit. those big lug style power blocks work pretty well but you need to think about the possibility of a short and if that happens the cable would burn back all the way to the battery or the battery could blow the lid off depending on how much duty it has been going through lately and the amount of gas it is venting. if installing the battery in the cab keep the venting idea in mind. there are some holders that will accommodate a couple of mega fuses if you require that much protection. also, there are bulkhead connectors that would allow the battery cable to be brought through the firewall or floor without the worry of a short from using a grommet.
these are all the reasons why newer cars have a fuse/relay box under the hood. they usually have a mega fuse built in early in the circuit for system protection.
mega fuses
https://www.amazon.com/Littelfuse-29.../dp/B001FXL4Q0
https://www.amazon.ca/Bussman-HMEG-B...28707664&psc=1
https://www.ebay.com/itm/NEW-BOLT-IN...-/151754544690
https://www.mouser.co.uk/ProductDeta...31qWWiEfCFNw==
bulkhead connector
https://ceautoelectricsupply.com/pro...ad-connectors/