Welcome to 60Patrol!
Congratulations on your new project.
Yeah, you posted twice, that's okay happens to newbies a lot when they don't realize their first posts are waiting to be approved when they disappear. No problem!
That looks like a nice Patrol you found. Ultimately what you do to it is entirely up to you because it's yours. But we'll be happy to play devil's advocate for you. It does indeed appear to be worth restoring. Not even needing a full frame off restoration really, just get the mechanicals solid and drive it with the patina. Many folks love patina, I'm one of them.
If you decide to modify with updated parts, there is no tried and true step by step method. You will be picking parts and guessing at their fit, hacking body, frame and suspension to make things fit with no engineering behind the methods. As a long time Patroller having watched this happen many, many times I can say that there has never been one that the owner was completely satisfied with after the modifications were done, if they were ever completed. The performance or control is not what they had hoped and they end up getting rid of it, or it sits and rots in a yard somewhere. One (very rare) Patrol junked, no longer to be resurrected. There have been a few heavy mods, monster trucks made where very little of the original Patrol is even still there. Those are fun, if you have the skill and money to put into them. Search here, you'll find several of these type of projects.
The most successful projects have been the ones that the owner has kept close to original or stock. You will find dozens of those types of success stories here. Some modifications or personal choices were made along the path but engine, drivetrain suspension, brakes are mainly original parts. We're happy to help someone locate the parts they need for these types of projects. These owners are then off enjoying their Patrol, on or off road. We sometimes see these Patrols resold and follow them around the country with their new owners, offering assistance when needed. These are the success stories we like to see.
Like I said, the decision is completely yours and we will be happy to assist whichever path you decide. The modification path sets you pretty much on your own though, because each mod is unique.