Communicate what's going on and you'll be in the clear. No matter how much control you'd like to have over this project, it's always a better idea to keep your superiors informed. That way, if you decide to call in sick on tuesday or wednesday (which you might) someone else at the office will have a clue about what's up. On thursday, some new inspiration will strike you and you'll charge into work with some fairly significant refinements to the general strategy, but, in general, this week is about being in close touch with your colleagues and turning your camaraderie into something of value.