Mounted my CJ-5 fiberglass tub in 87. It wasn't too hard, just time consuming. The wiring was easy though, I tore out all the useless stuff like heater, radio, keyed ignition, etc, and put in an aftermarket fuse panel, gages, and switch panel. If you are keeping all that stuff then I recommend a wiring harness from Painless.
'45 Ford GPW; '73 CJ5, 350/NP435/D20 w/Terlow gears, locked D30/D44; '13 CJ8, 304/T150/D20/D30/AMC20 w/locker and limited slip (T18 and Teralow gears in future); '88 Dodge RC, 360/NP435/NP205/D60s