This isn't a proper dungeon, though, right? It's for some kind of event thing or something?
If I did end up in this dungeon somehow, going left seems by far the better choice. Most of the time scry 3 is
better than one treasure, and whilst Goblin Camp + Defiled Temple together basically read "draw a card" if nothing else, playing an extra land can be pretty big a lot of the time too. From
Mountain Pass you can go diagonally across to Last Light Inn; sticking left for Balthazar's Lab is potentially the better option (and Reithwin Tollhouse is not half bad either) but that forces you into Undercity Ruins which may or may not be a lot less attractive than Circus of the Last Days. But then again, Temple of Bhaal will be brutal in a lot of situations; I'd usually rather have Ansur's Sanctum by far but I'd rather have the option of the temple than the option of Steel Watch Foundry.
I'd use this in my
Acererak the Archlich deck if I could; Ansur's Sanctum is probably a better wincon than Mad Wizard's Lair, and just in general this one has far better rooms (and specifically Tollhouse is really good, I'd probably almost always go Teahouse ->
Mountain Pass -> Grymforge -> Tollhouse -> Gauntlet -> Circue -> Sanctum, possibly sometimes Goblin Camp -> Defiled Temple -> Grymforge, but less likely what with
Crash Landing giving you a land).