Return to Osman and inform him you think you have a good disguise but you dont know how to OSRS gold get it. He'll tell you to receive some specimen of the individual and that should do the job. Go back and kill the"Chief Servent." He will not have healed since you last attacked him it shouldn't be hard. Take the hair to osman and he'll tell you there is a mage in the west who will transform you into someone else.
Go to the makeover Mage just north-west of Rimmington and then talk to him. Ask him/her if they can turn you into someone else. They'll tell you they need a specimen of the individual, three vials of water, and 1k for their services. Give them the things and they will create"Strange Potion." They'll instruct you to drink this just once you have to impersonate the person as every potion gives 10 moments of stolen identity.
Return to the hideout and try to open the door. Ensure you've got the Hideaway ring on and the hideout map in your stock along with the axe if you're utilizing woodcutting and strength plus a rope to utilize agility. Lower levels are indicated to cheap RuneScape Mobile gold get some food, adequate armor, and a good deal of both runes or arrows and teleport runes. You also need to be sporting the black robe top to be concealed as the servent.