I have a '78 FJ40 and a '65 FJ45 longbed pickup. My 'FJ40 has a PTO winch and ConFerr tank and rings in at 4550 lbs - so pretty close to an LV in porkyness. If you're worried about a couple of seconds in the 0-60 department, you're in the wrong 'hood. They're all gas guzzling slugs. I run 33x9.5 tires on my trucks just so I can drive 70 without feeling like I'm going to blow the engine.
In your '45, I would run minitruck power steering, which is defined as using the steering box from a '79-85 4x4 Toyota minitruck (Hi-Lux) and a adaptor pedestal to replace your OEM steering box mounting casting. You will need to do some fab/cutting/welding. I would not recommend Saginaw/GM steering, but some would. No power steering is going to give you exquisite road feel, but some (Toyota) typically feel less boosted than others (GM). You will find plenty of info on minitruck steering conversions all over Mud and the web.
I cut and modifed a '71 FJ55 steering column to work in my '65 FJ45 pickup, and while it works fine, it's not optimal in every way. In a perfect world, I would have used the original '65 column, but it had some issues. Any steering column mods will involve welding/fabbing/eyeballing and fiddling to get the wiring, horn, and dimensions correct. It may be the toughest part of the conversion, actually. Using the Toyota minitruck box does involve using all the OEM linkage parts and center arm, which some people abhor. So, there's no super-obvious 'best way' to do any of this.
Steve