For Roah, the best thing to do is wipe out all the goblins in the scantum first, she and her guards won't interfere. (If you're having trouble, keep practicing, it's not that hard when you get the hang of it. Especially when you can long rest in the middle of it.) Then you can attack Roah and guards and steal their stuff. Best cache of gold in the game.
The best way to play her, and the traders at the toll house and outside the scantum, is to trade with them for anything you want, then kill them later. You always get to loot back everything you sold them. If you just kill them, a lot of their wares disappear.
