If you can get together with 4+ people in a balanced group, you might explore early parts of Dragon Valley or head through Death Pass to Leto Lizard country. Leto Overlords are excellent EXP(Lineage2 Gold), very good drops, and not too difficult if your group is reasonably competent. The pit beneath the Ivory Tower is not too bad either, and spellbooks are always in high demand.

At the moment, our level(Lineage2 powerleveling) 33 Palus Knight is back to soloing. We have been hunting in Gorgon's Flower Garden quest from one of the guards at the north gate of Giran, Arrow of Vengeance. The mobs are not too difficult to solo, but there is considerable downtime and we have to watch out for people running trains. We took down a train of Bugbear and Harpies the other day much to the surprise of the dwarf who dropped it on us.

But it was touch and go and cost us a bundle in potions and DSS. We would much rather be grouping in Pilgrim's Necropolis, but our friends are 35 and busy doing their first Lineage2 class change quest. Well, we suppose it bears mentioning that Cruma Tower is also doable from 30-40. Personally, and for a variety of reasons, we do not recommend it.