According to the comments at the bottom of all of the pictures, on the link I provided, one was transported to a hospital by ambulance and one by helicopter.
Still too early for more info.
TRAFFIC ALERT: RV off roadway and into tree, suffering major damage, on US Highway 281 South approx. 4 miles south of Stephenville. Updates below:
(12:20 p.m.) - Units are clearing, with DPS still on scene investigating and a wrecker there to tow the heavily damaged vehicle.
(12:02 p.m.) - Report from scene - Appears there were two patients, both males. The passenger suffered serious injuries. Right front tire of RV is blown out, but it is not known if that was the cause of the accident. There were children's items on the bus but no children to be seen.