I'm a little to far to the north to pick up the Kleburg County Public Service system consistently but can confirm that the control channel of 851.05 is almost always used. PD, SO, TAMUK and FD are all active on the system. Talkgroups listed are all that I have ever received. My recommendation is to program the control channel frequency in as a conventional object and confirm that you can receive the control channel signal. If received then create a trunking system with all of the frequencies listed in the database. If not receiving signal, are you inside a building or outside? If can receive outside and want to listen inside then an external antenna will probably be needed.
For DPS, When driving through that area I'm able to receive the Corpus Christi Base B and the Falfurrias repeater. The repeater allows you hear both sides of conversation. There is however, as mention above, very little traffic on these channels. Typically only hear dispatches to accidents.