I haven't read Kerouac but I can say something about Virgil (prepare yourself for the wall of text, sorry).
As someone who had to study Latin in high school (yes we do that here) I preferred Virgil to other authors, mainly because he wrote fiction instead of focusing on corny love poems, war business or political intrigue. He actually never struck me as having a particularly unique style of metaphors though.
Detailed metaphors in general have always been preponderant in the ancient days, think of Homer as Malk said, or the use of kennings in Norse mythology. Maybe it's because before inventing complex new words they had to make do with the ones they had to describe something.
Anyways, the thing is this kind of long metaphors were either made to implement the evocative power of the story (Gilgamesh, Homer) for the sake of peasants, or to nudge noble people with cultural references (Virgil, the skalds, also Homer). But those times are long past, as is (hopefully) the need to nudge people so hard with your culture that they fall off the chair. And I assure you that even if I liked Virgil, his metaphors were alright with us modern students only as long as they were very short. Here, let me show you an example from Dante, Virgil's fanboy best buddy without consent:
"As in that season, when the sun least veils
His face that lightens all, what time the fly
Gives way to the shrill gnat, the peasant then,
Upon some cliff reclin'd, beneath him sees
Fire-flies innumerous spangling o'er the vale,
Vineyard or tilth, where his day-labour lies;
With flames so numberless throughout its space
Shone the eighth chasm, apparent, when the depth
Was to my view expos'd. As he, whose wrongs
The bears aveng'd, at its departure saw
Elijah's chariot, when the steeds erect
Rais'd their steep flight for heav'n; his eyes, meanwhile,
Straining pursu'd them, till the flame alone,
Upsoaring like a misty speck, he kenn'd:
E'en thus along the gulf moves every flame"
(my eyes are bleeding because of the English translation)
This is a (double) simile, not a metaphor, but it was a particularly infamous one during my school days because of its length and detailed references. Dante often took Virgil as inspiration, you (in my opinion) should not.
The metaphors and the style of these old works is beautiful, but they are too far away from us to be taken as a direct model for a new work (be it prose or poem).
All of this was probably unnecessary rambling but meh, I'm bored.