Lightspeed is also free money. They give $10,000 per person without taking any equity. Other than the requirement to primarily work out of lightspeed, the programs aren't mutually exclusive. So you could get away with working out of Lightspeed's office and flying to Boston weekly for the YC dinner. With funding from both you could even afford to pull it off.

I really don't understand this "YC or nothing" mentality. The funding to live comfortably really helps out, plus the free legal work. The legal work is what really kills you when you're bootstrapping.