A modular rig system assembled without use of a crane includes a platform and a mast. The platform has pin retaining structure. The mast is separable from the platform and has a transport foundation, a tower, an alignment actuator, a pin, and a piston arm. The tower has pin retaining structure and is movable relative to the transport foundation between transport and use configurations. The alignment actuator is operably coupled to the transport foundation to adjust positioning of the tower while the tower is at the transport configuration such that the platform pin retaining structure and the tower pin retaining structure are aligned. The pin selectively passes through the platform pin retaining structure and the tower pin retaining structure to couple the platform to the tower, and the piston arm is pivotably coupled to the transport foundation and the tower for moving the tower between the transport and use configurations.