Been thinking about your quest for a high speed willys. One thing i noticed driving mine around last weekend. It really handles quite well. Untill you hit a bump or pothole, then your sideways, shaking, and almost in the ditch. The main downfall about these jeeps other than the short wheelbase (not much you can do about that without a LOT of welding) Is the steering system is horrible. likely the cause for wandering, wobbling, and the afore mentioned bumpsteer. There is some tricks you could do to improve this. I've heard of a lot of people swap in a saginaw steering setup from a 1976-86 CJ. This would get you a far superior steering box thats actually designed for highway speeds. And eliminates the complex factory ross system with tons of seperate parts and joints that get loose and sloppy. This setup would be alot safer even at low speeds. and I think would really help keep that jeep on the road. Then if you wanted to have power steering. You could get a saginaw box with hydraulic assist. But you'd have to have a pump on the engine and run lines. Which wouldn't be a huge deal but to be simpler. Get an electric assist unit from a 2009-13 toyota. That just splices in to your steering colum and has 3 wires that need power. This could be easily found on ebay or at a junkyard.
Heres some videos I found explaining this process.
Saginaw steering. https://www.youtube.com/watch?v=SRD50RHsxZA&t=772s
Electric assist. https://www.youtube.com/watch?v=SUlt03cuzyA&t=1427s