Robocision: Thanks for reading. I was playing solo on a private game that I had created. I quit and came back and found no way to continue my progress. I'm hoping the only option to beat the game in multiplayer isn't to complete the entire game in one session. Is there a way to continue your progress?
Thanks again.
To elaborate on the answer from Faenrir: there are four entrances from town to the dungeons, which take you to the levels he posted. The entrances other than church have a character level minimum, but unlike Single Player, you are not required to come up from them first to open them. They exist as soon as you enter the game and can be used by anyone who meets the character level requirement (1, 8, 13, 17). The character level requirements are independent of difficulty, so once you move to higher difficulties, you can go immediately to dungeon level 13. It is common for high level characters to play only dungeon levels 13-16, never returning to the earlier floors even on higher difficulties.
Additionally, town portals never enforce a character level requirement, so even a level 1 can portal all the way down to level 16, if someone else opens a portal from 16.
None of this helps if you want to play only part of an area (say, 5-6), stop for the day, and return to the next uncleared level on the next day. However, if you complete levels in blocks of 4, you can avoid replaying areas.