Add 1-tile-wide corridors linking the rooms that contain the temples together in the Astral Plane, likely with secret doors so that monsters don’t start going through them. These give the player the ability to get around the Riders and go from the wrong temple to the correct one faster, but you run the risk of getting bogged down and surrounded if you use them.

It was pointed out that 1-tile-wide corridors may actually make things much easier on the player and would offer a much safer point to retreat to. Ideally they should be designed without long straight areas so the player can’t easily remove a bunch of monsters with a few well-placed teleportation zaps, but also be widened to avert the problem of being a refuge.