Any advice on how a rookie can tackle this behemoth of a game?
Oh God!! Where to start?
Unless you fancy a few days of reading guides on egosoft's forum, there's only one way to tame such a beast: head on. I would suggest you avoid plot-enabled games at the start as the plot doesn't really help, but throwing you all over the place. The humble merchant start is probably the best for starters. IIRC, you start in Argon Prime, one of the most secure sector, with a buster (med-fighter) and mercury (freighter). You can command the freighter remotely while flying the buster. Being in a friendly, relatively safe sector, you can take some time to become somewhat familiar with the controls and menus, and sub-menus and sub-sub-menus... If you don't mind not doing any fighting right away (probably a good idea since busters suck), you could sale the buster and get a discoverer instead*. Exploring will allow to get to know more about the game; the different races resources, prices range, weapons, ships, etc.
Before you know it (not really, but meh), you'll have a small fleet of traders
happily being shot in pirate sectors funding your growing empire. By the time you are ready to start building stations/spaghettiplex or buying capital ships, you'll know quite a bit more about the game. So instead of looking for vague advices, you'll be looking for precise info. Like, how many fraking crystal fabs you need to supply a 130 stations megaplex? Or which capital ship and weapons are the best to fight off the Khaak destroyer + carrier that just spawned in the sector housing your spaceweed complex?
I kinda got carried away here... The point being that messing around in-game is the best way to learn. Don't be afraid to mess up... you will even when you've become a "pro" and even if you don't, the AI will do so for you sooner or later (sooner being the most likely). Remember, losing is Fun... well the first few times anyway.
* Edit: Not sure you've got enough reputation at the start to buy anything. I wouldn't want to screw anyone over a simple oversight
Edit 2: Yup, got carried away and completely forgot OP. I didn't get TC as it feels more like a mod than a new game. Although, considering the patch 2.5 (I think that's the one) of X3:R was just that, a patch, and added several missions, a few weapons, sectors, ships and a shiny new HQ, I might eventually buy TC. If X3 was produced by EA, that single patch would have been sold in 2 expansion packs and 3 stuff packs... So I really ought to buy TC, if for no other reason than to encourage egosoft.
I got a question for those who played both: did they change PPC/other Cap weapon or are they still the wall of projectile killing FPS faster than an immobile shieldless jaguar raider?