The usual rule for car batteries is 18" limit from battery, but also you want the unprotected wire to be visible, not going into a wall where you can't see it getting that burnt look before it does catch fire.
I use ANL fuses for the big amps (over 50a) carrying wires such as for the inverters. They are inexpensive and found at car audio stores. Under 50a you see a lot of those glass fuses in twist apart holders, which are convenient at times.
I hook the ANL right onto the battery post (no holder needed for "strain" in my set-up) so no wire there at all.