im having fun so far just looking for collectibles and such but does it become a hassle? Is it worth it? Im still in the coastal forest (right about to open that LARGE GATE) with 62 percent and found the treasure map but still missing a relic 3 gps and 6 of the ghost hunter thingies.... Can I find all documents/ collectibles or must I come back at a later time? Seems like some are rather hard to find but thats part of the fun
Come back after you beat the game to finish up collectibles. They can all be found without a guide fortunately, thanks to the game's map feature which not only shows the location, but the specific area with a blue marker that can be seen with survival instincts when marked. The only thing that a guide is useful for is the various challenges, such as the "Ghost Hunter," or "Pyromaniac." Nothing is missable (aside from the Chatterbox achievement; although, some kill achievements are harder post-game), so don't worry.
One of the tier 3 skills marks all collectables (but not challenge things like the 10 fire statues) on the map. And if you're still having trouble, you can just set a waypoint for them on the map and use SI to highlight it with a big blue beacon.
A guide? The official guide is nicely written, it'll get you 100% pretty much and surprisingly is relatively spoiler-free - modern guides tend to describe every bloody cut-scenes, but this one just focuses on the game.
The collector's edition might interest you if you want Lara' necklace =p but I wouldn't pick it up for a ton of money put it that way.
You are so early in the game. Don't worry about finding every collectible right away, some of them aren't even accessible until you get some tools later in the game. And there is a skill you can get eventually that will reveal where the stuff is on the map, except for the stuff like ghost hunter, and even that stuff your instincts will highlight in the environment.
You can also go back to areas as you play, or even after you've beaten the game. I wouldn't look up where stuff is just because some of the fun is figuring out how to get something/where it is. Not only that, but it will extend the time the game lasts you. I don't understand why someone would complain about the hour length of the game and then proceed to use a guide to find everything.