therein
in this place
hinder
to prevent something from happening
crosses
As it is used in line 7, both intersections (of the maze), and burdens or difficulties.
mourn
to lament the absence of something or someone
retire
In line 10, to return back to a place of origin
allay
to diminish or put at rest
travail
to engage in painful or laborious effort
hire
Likely "reward." Early modern English sometimes uses words differently than modern English, and this can make interpretation more ambiguous. Consulting the Oxford English Dictionary can be a useful way to find historical definitions of poetry, and to make your own judgements about how you believe a poet was most likely using a word.
doth
does
