Another lovely simile is created when the speaker says,
There I elected to demur
Beneath a low-slung juniper
That like a blanket on my chin
Kept some dew out and some heat in,
Yet left me freely face to face
All night with universal space.
In the simile, the speaker compares the low-slung juniper, under which he decides to sleep, to a blanket that not only helps keep him warm, but also keeps some of the night's dew off of him. Further, in the passage above, there is also an example of personification. When the speaker says that he is left free to be face to face with universal space, he gives space the human quality of having a face. The speaker also personifies his memories when he describes them:
Inside the brain
Two memories that long had lain
Now quivered toward each other, lipped
Together, and together slipped.
The speaker seems to give these memories the physical ability to lie down, as a person might, the ability to quiver while moving toward one another, and the ability to kiss as they lipped together. Obviously, memories are not tangible objects that can move and shake and kiss, but they sound like two lovers here.
The speaker also employs irony by suggesting that although he is a "tramp," he has experienced many advantages that his "involuntary host" may not have. For one, "sleeping out" has given this homeless speaker the opportunity to witness the spectacular beauties of nature, like the "coalesc[ing]" of two stars in the middle of the night. We would not expect a homeless person to count himself as lucky as, or even luckier than, a person with a nice warm bed in a cozy house, but he does.