It’d be cool to have runic inscriptions, engravings, carvings, signs etc. in-game that you could read if you know fuþark. Even though Elder Fuþark wasn’t used in the Viking Age (Younger Fuþark was) I think that Elder Fuþark would be a better choice; I feel that it fits the English sentences better (it is more ‘complete’ and ‘compatible’) and is much easier to learn (you can learn it in mere minutes) and remember than its younger counterpart. I could even help you with it.
Or you could make your own fuþark.