I'll throw my $.02 in. I've got a '55 2nd, and it has, for the most part, been left stock. brakes, steering, and suspension were overhauled to stock specs, no disk brakes, stock master cylinder, stock manual sttering. I have added gas shocks, front and rear sway bars, steering stabilizer, and taller, wider, modern radial tires. I have don a non-stock engine overhaul, with a hotter cam, dual carbs, split exhaust manifold, and a hotter ignition system, plus I did convert to an alternator. The trans got swapped for an SM318 with the Borg Warner overdrive, which was an easy swap as the later trucks have an open driveline.
I drove this truck daily, rain or shine. The only time it doesn't get driven is winter and during the Christmas sales rush time, due to all the idiot drivers out during that time of year. It does get run at highway speeds regularly. The brakes and steering have never failed me.
Having said that, I'm not going to tell you that you shouldn't upgrade, nor will I say you have to upgrade. Do what makes you feel most comfortable. If you don't want to do the work, or would be more comfortable having someone with more experience/time do the work for you, I say go for it. In my case, I work on cars for a living, so I'm plenty comfortable with doing it myself.
BTW, I love the "Drive It" attitude you have, I stick to that myself.
