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If you don't have the slider brackets I'd be more inclined to find a different trailer, cost being the factor. Obviously the frame is rebuildable but to what cost extent.
I am using the original frame, axle and hubs on my "75. Most everything else has been replaced at least a couple of times.
The single axle is doable IF properly balanced and most any 1/2 ton pickup can safely handle towing the short distance you are doing. Presently I've not trailered mine over 10 miles to the farthest ramp.
If you were regularly trailering say more than 30 miles one way, I'd be really concerned and want a dual axle setup.
A dual axle setup may also improve your launching height problem by the ability to use smaller tires.
phat's suggestion of a torsion type axle is worth considering.
These are probably the only usable photos of mine.
