I've had DirecTV send a technician to us when we were on the road in an RV Park.
I've heard that since ATT is buying (has bought ?) DirecTV, DirecTV is modifying their customer support to fit the ATT model (we've had ATT in the past - never again), so they are unlikely to give you onsite support away from your home of record.
In many areas, you can find an independent shop that sells systems like music in stores and elevators, etc. and also shops that sell free to air satellite TV systems, etc. as well as DirecTV setups.
Many of these places will have technicians that can come out and help you for a fee, but with no hassle about being in an RV park.
Also, to get multiple satellites, you need something other than the 18" round dish setup.