Overlanding is about where you go, rather than what obstacles you drive over. Overlanding is taking the scenic route while avoiding unnecessary obstacles.
With this understanding, you'll be best served by investing your cash in making your D1 as mechanically sound as possible. Your D1 will need some off-road capability to tackle scenic trails, but it's there from the factory. It doesn't automatically need a lift. You're starting with a highly capable platform. Stock coil springs are longer and softer than most aftermarket options. Keep weight low and you can avoid the costs of stiffer springs.
For your intentions I'd stick with 245/75R16 AT tires. Invest in spare parts, training, overland books. Get out and practice driving your D1 off-road. Figure a way to sleep in the back or get a quality tent that sets up quickly. Avoid RTT if you can. Figure out your food, storage, communication, first-aid, etc. strategy.
For the bumper I'd stick with stock, buy some JATE rings for recovery, and maybe trim the bottom for better clearance. Aftermarket options are either for animal strikes (ARB), or rock crawling, and all add significant weight.
Steering and diff guards are good insurance.
You eventually learn that a lot of "mods" in the off-road world just look cool, but aren't well thought out.
It depends on how "overland" is defined.
Used to be people understood that overland travel was the more difficult but occasionally required alternative to sea, and later air travel; which is how I define it and why I enjoy it. You are at point A, and need to get to point B. For some reason or another, sea and air are not options. You're stuck getting there the old fashioned way, with all the trials and dangers associated.
Overlanding is
not meant to be desirable. It's meant to be the
last option when nothing else works, because it's unreliable as hell. That's why you get fucking paid to do it. Nobody else wants the job. Now, however, it's "glamping". I blame those nancy Australians and their "bush-gating" for that shit.
That's the word now, though, whether I like it or not.
Somewhere in the middle is what he's talking about and what you mention; taking that scenic route, which really is the heart and soul of off-pavement driving: Enjoying the outdoors. Everything you do to yourself and your vehicle should facilitate that enjoyment by mitigating terrain and travel variables.
All that said, you're on point. The first thing I'd do is cruise Ebay or Amazon for a full-color copy of that
"vehicle dependent expedition guide". That's about twenty years of experience shoved in your head in however long it takes you to learn and understand the contents. The author knows his shit. Don't buy a single screw until you've read it.
Absolutely let that man talk you
out of spending money.
Cheers,
Kennith