So looking at
this and
this it is clear that you can easily get all content for free.
Some may think it's not "easy" but really it is if you realize how that TP works out. You get it from completing missions, killing things (automatic from missions), and going places (also automatic from missions) and while doing so with one character wouldn't generate enough, you kind of naturally want to play the game with different classes because they play so differently and their crafting skills make them interdependent.
Between the two characters you get, it's 3220 TP. Spend 446 (current price) on a 3rd character slot and you can make a 1164 return. Get the mines of Moria expansion for 1495 and you can get 1535 more per character, and then you should have decent momentum going since the higher level play in Moria is more interesting.
However, it's even more open than this. You can repeat this on every single server but all the TP goes back to your one Turbine account. As the guy said, you may want to do that for the easily attained TP (i.e. not high-level reputation) to cover costs of something like gold cap removal (important to post-lvl30 play), universal storage (time saver for exchanging craft materials) and extra characters slots.
Obviously that gets to being grindy if you don't like playing again with different classes, but not nearly as grindy as other F2P MMOs I have seen since it all happens simply by playing through it. It's a lot of time, but taking your time, you'd easily get there. Paying merely gets you things immediately and allows you to disregard all but what interests you the most.
If I wanted to play it that much, I'd probably just go ahead and subscribe to make it a more laid-back experience. I'm not sure if I will get into this like that, but I just find it interesting that I can "evaluate" the entire game for free given enough time to do so. Too bad we didn't have something like this when I was a kid with endless free time and an adventurous attitude. It would have been really cool.