Level up your vanguard! Just do bounty after bounty, do every bounty you can every day for vanguard or crucible what ever you prefer. and then buy the legendary from them! ...Until you do the raid and get the good gear and all of your old legendary gear will be dismantled and forgotten about!...Also you can farm the hell out of rare engrams, and glimmer to level up your cryptarc, He has a chance of hooking you up with 3 Legendary at one time every time you level him up!...Pretty much spend your time doing all the strikes and patrols for bountys. Dont waste time pointlessly running around trying to farm for legendary, its not going to happen! Enough to matter anyways!