I’m not familiar with long-toed salamanders, but when I was in college, I had a trick that worked with my tiger salamanders. I had a light on the tank (not very bright, but enough to give them a “day”), and I set it on a timer to be on during the night. My room was in the basement, so it was already pretty dark where I kept them, but I covered them with a cloth to keep it really dark during the day (what they thought was night).
Basically, that flipped their day/night cycle so they were more likely to be active during the times I was awake. When I wanted to see what they were doing, I could lift the cover and watch them hunt or move around the tank (of course, sometimes they still just burrowed and hid).
I don’t know whether it would work for your guys. I know tiger salamanders can get pretty bold, so maybe it was just their personalities that made them more active while I was observing, but it might be worth a try.
