What area of Oregon are you in? You can put it in your profile so others can see too, unless you're worried about stalkers
I just rebuilt my engine and there's no way to tell without taking it apart except it's clean and runs well.
The most important thing to do immediately is make sure the fluids and filters are fresh. It's even more important after buying from someone else who may have been lazy in that regard. I'd replace the engine oil with Rotella T6 5w-40, and the oil filter with a nice WIX filter. Don't forget to fill the filter with oil before refitting. Then replace the air filter, fuel filter, power steering, brake, transfer case, transmission, front and rear diff, and swivel housing fluids. Remember the power steering uses ATF NOT power steering fluid. Make sure to check the coolant level too and make sure it's green, not orange or any other color. Spark plugs and wires may be good to replace too.
There are tons of mods but get all this done first. Then you can safely do mods like: front and rear bumpers, roof rack, snorkel, rock sliders, ceramic coated headers, stainless performance exhaust, better tires, better suspension, LEDs, high lift jack, winch, etc. Of course you may not need or want those. Stock Discoveries are extremely capable when maintained.