Front Suspension adjustment

Obviously I'm gonna have to build in some caster/camber but how much adjustment did the factory leave for my 73 Scamp?
Are you asking about range of caster and camber in the cams? About 1.5 camber and 3.5 caster. That's range of adjustment. The actual numbers depend on the ride height (because they change as the arms go up and down.) By ride hieght I mean shop manual ride height method- not clearance.

As far as your goals, its a little confusing. Most off-roading is not brisk in the challenging sections - it's often slow and steady, big on torque and articulation but depends alot on where you're at. Muddin and rock crawling are different setups, etc.

If you're looking for something more like rally, then find everything you can on the rally cars - the Shell 4000 website has some great articles on/by Scott Harvey from back in the day. There's also the Rally bulletins from DC/MP. Later ones include the Colts but still have the A-body stuff. Also I'm pretty sure the photos of Beckman's FIA car prep are still on line. Basically for current FIA Historics alot more safety is not only allowed but required. Back to your area of interest - stock based suspension is great for rally. Save yourself a lot of engineering and development time. As soon as you start playing with a suspension like your talking about (ie moving attachment points) then roll centers, center of gravity relative to roll centers, toe changes, scrub, etc all have to be figured out again.