[mwd_]

The drive up to Eureka may not even hurt your chances at coming up with one of those key insights if you've been working a lot. Sometimes breaks are good, and as others have pointed out looking at opportunity cost in terms of billable contract hours is deeply flawed.

It should also be pointed out that you probably shouldn't bother with the startup if all you care about is money and the expected value is exactly the same as predictable contract work. If it's worthwhile then either the payout should be significantly higher or there should be some reasons other than money at play that are again going to influence calculations.