I think the text would be challenging to an undergraduate unless a lecturer provided context and exegesis. Some philosophical texts, such as Descartes' Meditations and Locke's Essay concerning Human Understanding, can with some degree of success be tackled head-on. Others, such as Hegel's Phenomenology and Heidegger's Being and Time, can't. While I wouldn't put Adorno and Horkheimer in the same league as Hegel and Heidegger, the same point applies to A & H.
Odyssey
Plainly this is a vital point of reference :
Dialektik der Aufklärung a seminal text in twentieth-century intellectual
history, at the heart of which lies a mournful reading of the Odyssey. Odysseus and the
adventures of his voyage home provide Horkheimer and Adorno with critical material
for exploring the history and nature of barbarous enlightenment and their - seemingly
paradoxical - thesis: namely, that myth is already enlightenment; and that enlighten
ment reverts to mytholology. (Katie Fleming, 'Odysseus and Enlightenment: Horkheimer and Adorno's "Dialektik der Aufklärung"', International Journal of the Classical Tradition, Vol. 19, No. 2 (JUNE 2012), pp.
107-128 : 107.)
The German philhellenic tradition
Fleming again :
... closer attention ought to be paid to
the authors' choice and interpretation of the Odyssey. Dialektik der Aufklärung is, this
article shall suggest, a confrontation with the German philhellenic tradition itself,
from Hegel to Wilamowitz, out of which arises a powerful, ethical statement about the
nature of that tradition, and the politics and cultural identity in which it plays a central part. (Ibid.)
Hegel and Nietzsche
Special mention should be made of these two. Adorno and Horkheimer contrast their positions within the philhellenic tradition :
It is important to note, however, that here and particularly in his later work, Der
Antichrist (1888), Nietzsche does not follow Hegel, whose philosophical programme
ultimately justifies Christianity. In this respect their appropriations of antiquity
differ dramatically. For Hegel, the Greeks are proto-Christians. For Nietzsche, Griechentum [Hellenism : GT] is opposed to Christianity (which he places in the same negative category as
archaic Judaism).
But Adorno and Horkheimer's discussion of Hegel and Nietzsche is too complex to summarise adequately here.