Just thought I'd update this a little in case anyone was looking for the same type of fix that I was.
Craft of the Titans is awesome, but incredibly, brutally hard until you figure out some tips and tricks. It centers around the premise of the bosses being buffed up a ton, but so are you. And the normal mobs are much tougher and smarter, to the point where they will dig through the walls, put stones over lava, and even pillar up to you in the sky (that has recently been removed though). It is actually kind of fun to start new worlds every few days because your current world is just hopelessly fucked, until you sort of get the hang of it and want to play in earnest. I have restarted probably ten times with this pack, each time having learned something valuable to use the next time. I would definitely recommend watching a few Let's Play videos though, at least to understand what you need to do in order to get started and actually survive for a couple of days. Unfortunately there aren't many good videos for the pack, partially because it is pretty new, and partially because the vast majority of streamers not directly related to direwolf20 (Pahimar, Soren, etc.) are just so fucking bad at the game, or annoying (one guy apparently half-screams through his entire videos, like he's trying to be Pewdiepie on steroids or something...I shut if off after 2 minutes).
Before I mention a decent-ish streamer, the other pack I started playing due to seeing it on his channel is called Sprout. Way way less ball-busting than Craft of the Titans, but has a lot of cool and interesting stuff I've never even heard of. I sort of like this one better now just because CotT is soooo much focused on staying alive until you sort of become untouchable, and then you can start teching up. Sprout gives you plenty of time to fuck around without constantly worrying that you are going to get ass-raped. I'm honestly not exactly sure what the overall premise of Sprout is, I'm sure it says somewhere, but it is just fucking fun. And there are these ability totems you can find and equip that give you cool abilities like movement haste, mining haste, step-up assist, water breathing, and more exotic stuff like levitating all the mobs around you, slowing them, making them weaker, etc.
Anyway, I recommend both of them highly. Craft of the Titans if you want to get killed repeatedly until you get good enough, or Sprout if you like to take your time and mess around with a bunch of obscure mods. They both have a bunch of quests, although Sprout is way more like an RPG where you have to actually go talk to people, and CotT is just a massive (massive) list of quests that you can work through and get usually awesome rewards.
The streamer I mentioned is ToAsgaard, and I'll warn you right off he's probably got some assburgers going on, and his accent annoys me a little, but compared to EVERYONE else that I've tried to watch play Craft of the Titans, he's far and away the best. The others are either too annoying to listen to, or absolutely pants-on-head retarded at Minecraft. Seriously, go watch a couple first episodes of CotT LPs and tell me if they aren't almost all just fucking terrible. This ToAsgaard guy is very good at Minecraft in general, to the point where he's a little too good for someone like me to try to emulate, and he's super ADHD about some things (opening and closing doors for example, or running around jumping like a retard when he's wrapping up an episode), but at least he isn't wondering what coal does (slight exaggeration, but not much).
Here's his first video for CotT if you want to see what the pack is like. He also does Sprout so now that you have the channel you can click around at your leisure.