It's not a real desert, its a sand dune.
Caps 36 to 44: the Speed Bump for the Tims is memorization and recital of The Shooting of Dan McGrew, by Robert W. Service. From this week's Gamisode, there is a brief glimpse of the poem sitting inside a typewriter. Tim Jr. is tripping up on a line from the second stanza. I don't know how much of the poem they must memorize.