I am planning a ranger character around the premise that I can escape from a battle if I need to using alchemy for invisibility, and illusion for muffle. If I am in combat and use only a bow, and am overrun, can I cast muffle, drink an invisibility potion, and be completely undetected by the enemy so I can get away?

If so, do I need to perk illusion at all for muffle? I will not be putting many points into magicka - just enough for bound bow. (By the way, how much magicka would I need for the bound bow if I get the adept conjuration perk?)

Thanks in advance.