I have done both. I used a Painless wiring harness on my 59 because I wanted it modernized and reliable and of great quality. The harness is all of the above. Recommended.
On my 47 CJ2a I did my own wiring harness. It was very simple and very inexpensive. I bought a fuse block (not fused originally) and spade fuses at a swap meet for $8. I bought a bunch of wire at Harbor Freight for $14. And I bought of connectors from Harbor Freight for $3.99. That was it. Other than one minor mistake which made the thing keep running after the key was off, the wiring harness i created has worked just fine. I put it in a $4 plastic box with a printed card on it telling what fuse does what.
I bet your 48 truck doesn't have any more in it than my 47 jeep wiring-wise. Its easy to do if you just take your time and check off the wires as you do them. I even got those wiring looms at harbor freight for another $3 just to make it look pretty under the hood.
