I did pretty much everything else before heading to Maxos Temple, and was level 14 outside (entering completed a quest, which brought me up to 15). You could probably manage around level 11 or 12, though.
At the end of Maxos temple you can teleport to sentinel island (and back, until you reach a certain point, which you are warned about). You can mindread your first encounter there to gain a full level, so the higher level you are when you get there, the greater bonus experience points that will give you. Finishing Maxos temple almost brought me up to level 16, so I headed to the fjords to level first, rather than waste the mindread when I only needed 3k experience. I kept going, and managed to reach level 18 (for the last 4k experience, there were only level 21 imps available, which took a few tries to take out the first group).
Welcome to the forum.
OK ive played 3 characters through and working on a 4th!!!!
