The Saginaw pump will be a tricky one, on the older Ford diesels with V-belts you could use the bracket off an Econoline van and that will give you the Saginaw, but that doesn't work with serpentine belt drives. You'll probably need a special conversion pump, luckily that is readily available from vendors like PSC. Then there is the matter of plumbing the Saginaw into your system, with just a steering box you can use an off-the-shelf pressure hose for an Econoline van and be done with it, but there's no factory application that uses a Saginaw pump with the oddball F-Superduty style hydroboost (SAE o-ring ports for the hoses, as opposed to earlier SAE flares and later metric o-rings). Your best bet there would be AN- adapters on both the pump and the hydroboost unit, and then just AN- line of proper length and size between the two - not quite an off-the-shelf solution, but still very field serviceable by anyone who makes hydraulic hoses (big truck repair shops and service trucks, NAPA stores, HVAC outfits, etc.) because the adapters are non-wear items and it's just the line that would possibly need replacement some day. But honestly, having ran both the Saginaw and the factory pump on the same truck, I don't think the Saginaw is all that needed, maybe if you ran steering assist cylinder on the front axle, but for just a hydroboost setup the factory C2 type pump is more than adequate.
Another cheap brakes upgrade on these trucks are the rear wheel cylinders - you can replace yours with the DRW-specs ones, they are a bit larger and thus will give you some extra shoe clamping force at the drums. Direct bolt-on deal, no custom work needed, if you're due for new wheel cylinders soon might as well grab the DRW stuff. Can't use the DRW drums and shoes though, not on a SRW axle.
Regarding the spare wheel, we actually don't have rear-view mirrors on any of our trucks, we rely solely on the external ones to see what's around and behind us, so I know you can do just fine that way. What I was referring to was trying to back into (or out of) a tight spot, basically situations where any visibility towards the rear is welcome - that's where it can get a bit annoying looking over your shoulder to the right and seeing nothing but that huge spare wheel. But you may never run into such a pickle, and a decent backup camera makes all this a moot point anyways.
