Last year I was there for the 2nd weekend heat & we couldn’t really escape the heat of the tent. But when the sun came up my wife & I just got out of the tent & put up our UV beach umbrella similar to this one & we just napped underneath the umbrella outside of the tent. Out of the tent heat, out of the sun, plus had a nice breeze.
That you can take on the shuttle bus? None. Maybe a Sport/beach umbrella.
You can build a pvc shade structure pretty easy. A simple tarp, pvc setup will work. The ground is hard, bring some kind of heavy duty tent/tarp stakes.
Anything other than an EZ brand EZ up will not last 4 days without proper care. Eg. you must stake down each foot through both holes. Run all the guide lines it has, make them taut and hang tags for visibility. The cheap $30 ones will fall apart in the wind. You must add guide lines to keep the stress from the wind even, a strong gust will lift, tweak, and destroy the cheapo s. Strong guide lines keep the stress on the wires and upper frame, as opposed to the long spindly legs.
Get this umbrella One of my friends has it and it is pretty awesome.