Level 40 to 80 is the most difficult time for the solo knight. The enemies get tougher and more numerous, but our knight's improvements are quite gradual. We already obtained good gears during early game through vendors in Blackshire, Whitecap and Kriegspire etc. So there is no major upgrade to items. Our main offensive bow skill is lacking as we had to get expert and master in numerous misc skills. This means our bow is only at rank ~25. Not nearly fast enough, even with haste.

One of the problem is that most enemies in high level dungeons have a ranged attack as well as strong physical attack, such as the doom knight family.

Another one is volume. As the monsters become more durable, their numbers remain the same. As it takes much longer to dispatch stronger enemies, I find that I get swarmed very quickly.

The interesting thing is that as difficult as it is, once I get rank 45+ in bow and a bow of swiftness or darkness, the game becomes considerably easier as I can kill most mobs and remain at full hp.

I am currently level 60 (eligible to train to level 66). In about 30 levels and the correct items, I can probably get to late game and clear Dragonsand without too much trouble.