River Shack-The best and richest base location

This is, in my opinion, the absolute best location to set up your base. And it's no other than the magical river shack, at 51W 19S!

The basics, what you need to do before getting there.

So, depending on how far away you spawn, I do recommend taking a couple days to collect some resources before making your way to the shack. You will certainly need food to sustain yourself, and I also recommend making a bow and some arrows as soon as you can. Depending on how you'll approach the shack, you may come across snakes or jaguars. So a bow is really useful, as you can one-shot them with a headshot! You will also need to collect many stones, sticks and ropes, to make your initial pickaxes, before you're able to get bones to make better ones. Also make sure to take any molineria and plantain lily plants you find.

Stone pickaxe: 2 stones, 1 stick, 1 rope
Bone pickaxe: 2 bones, 1 stick, 1 rope
Wooden bow: 1 long stick, 1 rope
Arrows: 2 bird feathers, 1 small stick
Plain molineria bandages: You click on the molineria leaves in your backpack and press on craft, then craft the bandages
Lily dressings: You combine a lily plant with a plain molineria bandage

Yay, you're at the shack! Now what? What are the first steps?

Congratulations, you've successfully arrived at the shack, hopefully in one piece!
Take a look around, there are a couple items to loot. You'll also see that there's beds, so there's no need to make one. But what you should get to making ASAP, is a frame and then a wooden roof on top. Now you can save your game! (just look up at the roof and press E as prompted.) The next step is to make a fire right under your little shelter you just made. Now you can cook any meat you've collected. When you finally have your bearings, head to the side with the coconut trees, and grab a few coconuts. You can lay some empty coconut shells around, so that they can gather rain water, which is clean water for you to drink. Also, make sure to keep 2 shells to place on your fire. Now you can also boil water, and make soups and brews. Soups are much more nutritious than eating stuff in their solid form. Finally, you'll need a full unopened coconut, to make a bidon, which you can fill up at the river and then fill up your fire coconut bowls.
You may have noticed that the area seems pretty safe, however sometimes natives could attack, and right behind the shack, jaguars do tend to prowl. So the next step is to start making a fence. You can pick either the bigger or smaller one, both work. The shorter one is much easier to make also.
There are so many resources all around you, from banana trees to tangerine bushes, to capybaras, to caimans! (The caiman is along the shore where the coconut trees are). You may also notice how many macaws there are.... Which is amazing for arrow making and never running out of meat! Get hunting and stock up!

A little more info on the culinary stuff...

I strongly recommend making your foods into soups. All meats are superior in terms of nutrient giving while in soup form. Another amazing ingredient you can make into soup, is the monstera plant seed (The long green one). Those buggers give you protein! And what's even better is, they don't spoil! EVER! On the topic of not spoiling, the soups also never spoil or burn. You can just leave them there until you need them. Later on in your game, I also recommend making a mud fireplace, just to have 2 extra spots for soup. For that you'll need a mud mixer first.
VERY IMPORTANT: Make sure to always keep an eye on your fire. You'll want to fill it up before it goes out. You simply put small sticks, sticks or planks on the little circle on top of the fire, until the meter is gray.
Also, if you just want to cook your meats and eat them as they are, but don't want them to spoil until you're hungry enough to eat, you'll want to go to the bamboo forest across the river, and find the bamboo camp. You'll unlock the smoker. Smoked meat does not spoil.

Sticks and stones may break your bones... Unless you wear some armor

Armor! Very important.
I recommend either bone or armadillo armor. Armadillo is a little better, i think. You'll need to kill 4 armadillos and take their shells for this one. They're currently bugged and do not die with a head shot, at least for me, so you'll need to chase them and walk up to them until they turn into a ball, than smash them repeatedly with your axe. They will eventually die. You harvest them and keep their shell. Then you'll need 1 banana leaf and 2 ropes to make an armor. Do that 4 times for all limbs. For bone armor you need 3 bones, 2 ropes and 1 banana leaf.
Make sure to occasionally check your armor's durability, the last thing you want is for it to break right before you get attacked by a jaguar.
Also, to check for leeches, you need to click on the little "turn off" armor button, and when you're done taking them off, you can click it again to make your armor visible again. Leaving it invisible does not mean that you're not wearing it afaik.

Out of energy and short on proteins?

You're in luck. All around the area you'll find big logs on the ground, that have mushrooms on them. You'll want the yellow mushrooms with the big head. Then you'll also wanna go to the big big tree right behind the shack, the one with those brown vines, and you'll want to grab the blue mushrooms growing on it. Both those mushrooms give energy, the blue ones more than the yellow ones. But they're good in a pinch!

What to plant?

You'll want at least 2 or 3 monsteras, 3 molinerias, 3 plantain lilies, and maybe some orange and banana trees if you'd like. Nut trees are unnecessary imo, they dont even drop nuts that often. You're MUCH better off getting your fats by eating coconuts, which you can find all around you. (IMPORTANT NOTE: if you dont see any coconuts on the ground, look up at the coconut trees and you may see some! All it takes is one arrow to shoot em down!)
Don't forget to water your crops and make a composter for fertilizer. You can put anything organic in the composter, from spoiled foods to feathers, raw meat, whole macaws, etc.

Safe crossing of the river

You see the bamboo forest right across the river. You can't help yourself but want to go get some nice bamboo to pretty up your buildings. But there's piranhas!! So you gotta be safe. That's why you first ought to build some platforms in the water, and make a bridge. You will also need a sled. Sleds are very useful for carrying resources such as big stones, long sticks and logs. I prooobably should've mentioned them earlier, huh? Yeah! Don't go resource huntin' without a sled. You can carry way more things in it than with your hands.

By now, you should be all set for life

Should you follow all those steps, by now you should be really well off, with a seemingly endless supply of nutrition all over, a well guarded fort, and lots of resources. I wish you luck on your future adventures!