A modular seat/bed conversion assembly for use within the interior of a recreational vehicle. The seat/bed conversion assembly comprises a substantially horizontal seat configured to pivot forward substantially 180 degrees about a first axis; and a backrest comprising a first section, at least a portion of which is configured to pivot in a first direction about a second axis from a first position to a second position, and while in the second position, the first portion is substantially flush with and forms an extended substantially horizontal seating surface with the pivoted seat; and a second section configured to rotate in a second direction opposite the first direction between a substantially vertical position and a substantially horizontal position.