To the OP, good luck on your quest. It's not a hard one but as you know and have read there are several ways to skin a cat and even more ways to cook one.
I'm the owner of a '99 3rd gen with a 5 speed and e-locker. It's mildly modified with taller coils, sliders, bumper and homemade skids. I feel the 3rd gens are one of the easier vehicles to build up and make items for. There is also a lot of aftermarket support for any avenue you'd want to take. Once you get into newer vehicles their buy-in price increases greatly, they get bigger and heavier, harder and more expensive to mod, not to mention there seems to be reliability and durability issues when you go newer.
I've got a wife and 2 kids (almost 3 and 6) and the 3rd gen is a little small when packed up for a trip. We make it work but I've had to build a roof rack and sometimes use a hitch basket. Our trips can be purely road with hotels to 3-5 days of boondocking. We've packed and traveled for years so we have what we bring down to a science. It's a combination of light weight and space saving because of room and my patience.
I really like the interior room of the 4th gens and would take one if someone wanted to trade. I sleep in the 4Runner if it's just me or me and my wife. I'm less than 6 feet tall but if you're near it or over it you'll need to make provisions to sleep in the back. Sleeping platforms are neat but I require the rear seats to be up because of the kids and also because of the kids I need the interior room that a platform or drawers would take up. Front seat room is also marginal and at 5'10" and 180 pounds it feels a little cramped. For me a 4th gen is WAYYY more comfortable.
Wheeling a 3rd gen is fun and for the west coast it's a great size. Trails tend to get narrow in places depending where you are and being too tall could cause issues. They have great ground clearance so you don't need a massive lift to do moderate trails. Less lift helps with fuel mileage and you get to retain stock quality parts instead of replacing them with so-so parts that break or wear out. I'd say for "Expo" use keeping tire size under 33" is the key to happiness. Hopefully there wouldn't be the need to regear, your drivetrain and steering is happy, you can fit a spare in the factory location, you can keep the stock wheels and hopefully eek out the most mileage from the slightly undersized fuel tank.
The 3rd gens and 4th for that matter are truly go anywhere vehicles. They have enough power to move what they are while maintaining economy. There are great things to be said for the larger LC's but the cost to build them along with the economy is too high for me to consider.
Green seems to be a popular color.
Come to think of it, everyone has 3rd gens. If you end up with one you'll be in good company.