2 Was for like need enforced to disarray:

like > [a] similar disarray > disrobe, divest herself [of armour]

3 Tho, when vailed was her lofty crest,

Tho > Then vailed > lowered; doffed crest > helmet

4 Her golden locks, that were in trammels gay

trammels > plaits, braids

5 Upbound, did themselves adown display,

adown > down display > spread, spread out; display

6 And raught to her heels: like sunny beams

raught > reached