Are there any shortcuts or healing areas within Naraku though? I've entered the 3rd Stratum, and it takes forever to go back up.
It takes like a minute, tops, to ge out of Naraku and go back to the Barracks. There are shortcuts in each level that make the backtracking much faster.
But after you play for a while and go deeper down that dungeon, you'll unlock something to travel faster in certain locations.