You don't really have to fuse the line from the battery to the new fuse panel since everthing ran off the panel will be fused from the panel its self. If you are going to run the lead a long ways, under the rig, through the firewall, I would run it through a pies of hose.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed