the rest(ingplace) is maybe 'losing one's rest'.
The mountain shows the stuff the earth is made of inside: one can read the entrails of the earth.
I think 'stripping the bed' means something like losing one's rest. Caused by the feet: a sense of reality (bottom line), insights (line 2), superficiality (line 4). And line 3: to see through people or things, so break away. (supplemented by 52.3: don't suffocate yourself by a perfunctory life)
Line 1. Zu is foot, but in many Chinese words it is used to indicate realism. Bu-zu (not-foot) is 'of no consequence'. In this line the bed is stripped not 'at' the foot, but 'through' the foot, so I thought it was permitted to use this 'realism'-meaning here.
'One can see sharp with the heart. What is important is invisible for the eyes' (Antoine de Saint-Exupéry)