Hey Mike!
First, let me say thank you for your service. That is/was a tough job and thank God we have men such as yourself who took on the challenge, not sure I could myself.
Second, welcome to the Hundy club. I'm a pretty new member myself but have admired them for years and was excited when things worked out so I could acquire one also. Mines a 99 also so if you have any questions related more than happy to help.
Sounds like you got a good one. Mileage is not bad at all and if PO did the maintenance as you've stated probably not even had half it's useful life yet. Price was fine - if you're happy with the deal then whatever anyone else thinks doesn't matter.
As for what you HAVE to do to build it up to start enjoying - absolutely nothing!!!! Straight from the factory the LC is one of the most capable consumer level rigs ever built. Camping grounds, fire roads, light off-roading, and stream/river crossing is what it was built for. Military, service orgs, and companies use the factory setup all over the world because again, that's what it was designed for.
Now, if you want to cross streams deeper than 24" then you will need to make sure door seals are tight, breather tubes are routed correctly and maybe extended, and look at adding a snorkel for the deep stuff. If you want to rock crawl over more than 6" ledges or rough fire roads then you should remove the factory running boards (a lot do this regardless, gives the truck a more aggressive appearance) and add a set of sliders. If you're looking to get more aggressive offroading then start thinking about things like bumpers to give better approach/exit angles, upgraded suspension to compensate for the weight of bumpers/gear and extended wheel travel, exterior tire carriers so you can change one should something go wrong, and winches to get through the really rough stuff (or recover the buddies Heep or Exploder who thought he was all tough or something

). After that it becomes how many creature comforts and how long far away do you want to get. The options are limitless - roof racks, drawer and sliders in the back to store gear, dual batteries, fridges, etc. Spend some time on the forum looking at other builds and you'll find lots of amazing ideas.
Best wishes on all your endeavors!