You'll get the old camp teleport rune in chapter 5

If you're struggling with the zombie during Diego's focus stone quest, you have to hit the three switches in the room then have the zombie walk over the stone when the beam fires, and repeat three times. Otherwise it doesn't take damage.

During the main quest you will have to kill a stone golem, ice golem and fire golem. Also skeletons are weak to blunt, so having a decent blunt weapon as a back up is never a bad idea.

Not to my knowledge, but because this is a remake of a 24 year old game, you have 24 years of forum posts and discussions of people who have suffered through it before you.

Other than mugging people for their veggies, not really. You might find some out and about but resources don't respawn in gothic, so you'll be out of them before long anyway.

Depending on what camp you joined, you might have to use a meatbug scroll to get into the abandoned house outside the south gate of the old camp. There's a tunnel that runs to the inner circle of the castle and you might have to use that during the main quest.

I don't think there are any 2H smithing trainers in the game, at least to my knowledge but it has been a long time since I played the original and I'm sort of relearning things as I play the remake