I've learned to look at them before I get my map to see whether there will be potential traps (like the inside/outside corner situation you mention at the Stockade). There were so many on the Brown course!
You also need to know the symbol for underpass for sprints since it isn't on ISOM maps.
That said, I may not have noticed the upper/lower symbol...
I too took a while to find the start triangle! Found the controls near the end and worked my way backwards from #6 to find it.
Jon was thinking next time we use this map, we should do an example of the bridges that go to a number of West Point buildings (another ISSOM-ism) in the meet notes. It's there if you know what you're looking for, but we don't often encounter that symbol.
I do the same thing with descriptions - scan for inside/outside corners, upper/lower, top/bottom...then try to remember what I saw as soon as I get the map and start running too fast to actually think...
I'm very good about checking inside and outside corners but I forget to check for up/down in multi-level stuff, where knowing well ahead can make a pretty good difference in route choice.