You can buy the quest items from the Shop, however I think we might be changing that to the old quests because they are cool and fun to do 🙂
As far as NPC levels, as Alkien said you can see the minimum and maximum level of NPCs when choosing to teleport from the Gatekeeper, and you can also figure out the level of the NPCs from the color they appear:
(- means lower level than you, + means higher level than you)
- Blue: -9 or more
- Light Blue: -6 to -8
- Green: -3 to -5
- White: -2 to +2
- Yellow: +3 to +5
- Light Red: +6 to +8
- Red: +9 or more