I would like a sightseeing mode to look at the graphics.

[Niwashi]

Have... you ever actually tried this

Yes, of course I've tried it, which is how I found out. Up until the final boss dies, the Return skill takes you to the entrance, but once the dungeon is completed and the exit portal appears in in the final boss room, Return takes you there instead. It's possible dying may still give you a chance to resurrect at the entrance, but I don't remember for sure, and if you were alive at the end of the boss fight and there's no more mobs around, that's not an option anyway.