Here's a slightly different way that I see what's described in the prologue (or epilogue that's placed at the beginning).
Ennis is all about economy - the economy of saving last night's coffee, of using a pan that most of us would have thrown out or given away a long time ago, the economy of motion when he pisses in the sink because it's right there to use (and it does make me assume that there is no toilet in the trailer). The economy of knowing how to use the dream of Jack just right, so that it stokes his day. He doesn't dive into the remembrance of the dream too fast and use it up, he economizes.
And while I sure don't ever wish for the life he has in that trailer, I actually get the sense that even though he's living this very isolated life in this wind- and gravel-battered micro-trailer, that that's not too bad in his book, because he is living more in his memories of his times with Jack, than he is in this present-day world. So it doesn't matter (much) if he has very little, or that he's about to be uprooted to his married daughter's, because his valuables are completely portable and ever-present.