Welcome to the forum! Congrats on getting the new Runner, that's one heck of a graduation gift.

I too am 2wd and can perhaps lend some further insight about the questions you have asked. First, don't be afraid to take your truck off-road. All 4Runners (yes, even 2wd) are very capable vehicles and you can have a lot of fun as long as your smart about it. That being said, don't ever wheel alone. You should always have a friend accompany you in your off-road excursions, preferably a friend with a 4 wheel drive vehicle.

Your domain is light trails/log roads, sugar sand, 45 degree hill climbs and small patches of mud. Leave the rock crawling, creek crossing and all out mud bogging to those with 4 wheel drive.

IMO your first mod should be a good set of quality All-Terrain tires. Most of the gents here on the forum prefer either Goodyear Duratecs or BFG All Terrains. I personally run Nitto Terra Grapplers in size 285/70/17 and I love them. I just put them through the paces last weekend in Ocala National Forest and I hung with several other 4Runners (all with 4wd) without issue.

Here are some videos from over the weekend. Enjoy!

4Runner Hill Climb in Ocala National Forest - YouTube
4Runner in Ocala National Forest - YouTube