Re: Do you mention being a drummer on a day job interview?
I've always disclosed my drumming to potential employers, never had huge gaps in employment like yourself, so I've never had to explain that, but at the same time, I feel as though the experience I've had as a musician is valid work experience that can be applied to day jobs. Booking gigs is sales and coordinating. Promotion is marketing. Fans are networking. Rehearsal is preparation. Sell interviewers on these aspects and destroy any misconceptions they may have about the stereotype.
I'm in your category of 20's and early 30's who's always looked for work that allows me the freedom to do my thing. I've passed up promotions and advancement to maintain this freedom, but also been very fortunate in finding work where my employers embraced my passion and have allowed me time off to tour, do press things, or simply duck out early on a Friday for an out of town gig. Mind you, I work in film and television, I'm not sure I'd see the same kind of support in an accounting firm.