The directions this quest gives or has available for some conversations is really insufficient for actually finding the locales it's pointing you towards in the case of the Romithren Monastery and Seitur. The directions are erroneous for the former and generally unhelpful for the latter.
Romithren Monastery is described as being to the east of Nethril Plantation, when in fact it is to the East-Southeast. Really it should be a dialogue topic so you can ask people at the aforementioned plantation and/or towns where it is and they can give you detailed path instructions a la Punabi and Sulipund (first ones I could think of) in the main game. Screenshot attached of directions and in-game location.
Seitur is described only as being on the "east coast" of Morrowind, which covers an extremely lengthy line (which becomes even longer the closer you look at it, but I digress). It makes sense this random blade-soul soul-blade wouldn't really have a grasp on Morrowind geography, but it would make sense that you could ask people on the east coast of Morrowind where Seitur is (with presumably most people other than scouts having no idea if it's far away from where they are, with maybe more specific answers as you get closer).