Paul,
Definitely get a receiver. If the cable is run and the sensors installed, the hard work is done. You can hook up the receiver and display in short order. Hopefully the batteries still work in the sensors.
I would call Paul at the address below. I bought my system from him and he was very helpful including answering my questions on the installation.
Paul D Kintigh
RV & Tire Monitoring Specialist
Bob Dickman Tire Center
www.dickmantires.com
1 800 257 8430 Voice
1 541 998 3906 Fax