Well I am now lvl 76 and I have completed all my solo quests I can find- all I have left are instance quests (which if i do will give me around 1 lvl) which means what do I do for the rest of the lvls as I have completed the quests in all the areas? And tried to grind a bit yesterday but found it extremelly slow going.
This is a MMO - there are no holes in the lvling curve. Just that some parts are better filled with solo quests (Tortage and early zones) and some with group quests (all of the higher level zones).
At those levels you have TONS of group quests, which would take you to level 85 or 90 if no level cap. Just in Khesh - Onyx quests + Scorp cave + raiders + outer zone are worth the xp you need to level. Add the Atzel quests and you're set. A lvl75-78 group should do fine.
Start looking for some friends and kill those mobs.