At this point you are probably feeling like you are starting to outgrow Eltnen.  Once you get to your mid-30s you will be switching back and forth between Eltnen and Heiron. There really aren't enough quests in Eltnen to level on questing alone so zone hopping and dungeon crawling are your best options to make it through to level 40. In your early 30s, Agairon Village has a good amount of content and it's the perfect place to bind as you explore the surrounding part of the zone. At level 35, take the time to check out Geroch Caldera and the Kuriullu Mountains. On the road to Herion, you'll find another small quest hub and a field of level 36 griffons.

For the groupers that don't want to run through the dungeons and higher level duos, beyond Geroch Caldera is a whole epicenter of group quality mobs.  Kaidan Headquarters has mobs levels 37 through 40 and offers great rewards for those who roam through here.  You can pick up a couple of quests for this region, including the one that rewards the Commando Boots that give a 20% speed increase, at the Eltnen Observatory. As you get closer to level 40, you will probably spend less time in Eltnen, but don't forget to come back to check for higher level quests. Being such a large zone with a huge level range, there are often little things that we can miss the first time through!