I'm on the very end of High Road and I was wondering how long Avalon was compared to other worlds.
I have found each world tends to take a little longer to progress though only because of the difficulty it presents. As you progress though the spiral it's also possible you will need help more so it's becomes a waiting game also. Avalon has a few cheating boss battles to get though also and they tend to slow you down.
Those with the best gear set up, an active friends list, great pets etc. won't have any issue speeding though content, they also typically only do main line quests and no sides.
Really it is difficult to say how long a world will take an individual player because too many things to consider.
Well, it all depends on how hard you work but you say your only on the high road? You have a long time to go. You have The Wyrd, The Wild, Abbey Road, Dun Dara, Dun Scaith, Outer Yard, Lake Shore, Catacombs, Crystal Caves, then the final dungeon... Just keep working.