Can I add remote/keyless entry to a 2001 Camry?

=========== No. I t is not permitted by the authorities. Of course you can add keyless entry. The Camry already has the magnetic door latching mechanisms. Main point is to be careful in selecting an experienced installer and a quality system. "Hacking" into the wiring can create many problems that are difficult to diagnose and resolve later. Find someone whom you can trust not to damage the electrical system.