Factions and timing and experience so far

So, I didn't really get there were factions until level 40.

I had moved on from Horns of South and then realized i could have joined keepers.

I went back and did that and it's one quest? Meh.

But Alchemist's seem more involved? So I am enjoying those so far. Is that part of fixing the druid temple in horns of south?

Are the geographers a faction? I did Lancelot tomb and I find notes from them... maybe i"m daft, but what do I do with them? Can I meet a geographer?

I'm still doing act 2 and level 50. Wondering what other people found with factions? Fun? Did I do them too late?

I think there is a Dail Raita one too? Any others I missed?

It's not a faction, >!but I did meet Cai and the red death dude. It was fun to find a hidden skill tree.!<