As a protectee under the Secret Service Act, Hillary Clinton might serve time in her "gilded cage" mansion in Chappaqua if convicted a felony and sentenced to prison.

Under the Secret Service Act, Hillary receives lifetime Secret Service protection as a spouse of a president.  There is no provision in the act to terminate protection, even upon a felony conviction.  The Bureau of Prisons (BOP) would therefore have to decide how to incarcerate someone with a Secret Service detail.

If Hillary were sent to a regular prison (likely a low-security Club Fed), it would be difficult for the BOP to accommodate the Secret Service with their weapons and communications.  Most likely the BOP would decide to create a special home confinement arrangement for her similar to that allowed in some cases for pre-release inmates.  The BOP regulations provide that inmates may serve up to six months of home confinement, which includes surveillance or other monitoring methods.  Given the conflict between the Secret Service Act and criminal law, the BOP may elect to create, in effect, a special private confinement facility at Hillary's luxury home with an inmate population of one.

There is yet another problem for the BOP.  The Criminal Code has specific language (Title 18, §3621) that prohibits giving special treatment to the rich and famous:

In designating the place of imprisonment or making transfers under this subsection, there shall be no favoritism given to prisoners of high social or economic status.

The BOP may elect to ignore this provision in order to accommodate the Secret Service.  This all presumes that the Justice Department pursues a successful prosecution and also that Obama will not pardon Hillary.