Final answer:
Axons of preganglionic neurons travel to the sympathetic trunk through the white rami communicantes, which are myelinated structures connecting to the sympathetic chain ganglia.
Step-by-step explanation:
The axons of preganglionic neurons in the lateral gray horns of T1-T12 and L1-L3 indeed travel to the sympathetic trunk via the white rami communicantes. These structures are myelinated and provide the short connection necessary for the central sympathetic neurons to synapse on the ganglionic neurons in the sympathetic chain ganglia. Once the synapse is made, the second neuron, known as the ganglionic neuron, will project to a target effector through the gray rami communicantes, which contain the unmyelinated axons of these postganglionic fibers.