Health-care and other benefits would be priced into any contractor's fees. IE, for a full-time job that paid $100k + benefits, you'd need ~$160k on contract to make up for the additional taxes, self-paid benefits, etc.

Looking at peers who struck out on their own, you can make good money as a contractor, but you typically need to be top of your profession and able to command massive fees. And like any business owner, the pressure to always have too much work usually ruins any chance at using the money for longer, more extravagant vacations.