Conversation so far:
What are trail rides in the Houston Livestock Show and Rodeo event?
The trail rides range in size from a dozen to over one thousand people who ride on horseback or in horse-drawn wagons from various areas of the state to Houston.
Are the trail rides which are done prior to the Houston Livestock Show and Rodeo open to the public?
Do people ride on horses in the Houston Livestock Show and Rodeo trail rides?
The trail rides range in size from a dozen to over one thousand people who ride on horseback or in horse-drawn wagons from various areas of the state to Houston.

Question: Is there a charge to participate?
Self-contained rewrite: Is there a charge to participate in the Houston Livestock Show and Rodeo trail ride event?