Basically, yes, I like it. I do have some details. First, Kant's Ding an sich is famously the thing in itself, rather than "on them." It seems to me likely that Rilke is using an sich thus. Stroked for schmeichelt - maybe. But I'd prefer "quite alone" to all alone. "Never must he forsake her" is all well and good, but there's no nie in the German. Maybe "and he must not..."?
OK, that's about it. Hope this helps. Everything else I think is very nice. :-)