A Camry or Accord will run fine on LPG. You need a tank, vaporiser/regulator, gas injectors installed in the inlet manifold plus a filling port and the controller and flow solenoids fitting. The system, with a tank of LPG, will probably add 100kg+ to the weight of your vehicle and you will lose some luggage space. The systems are generally reliable and you can switch over to petrol in the event of an LPG fault.
Normally the car will start on petrol and then automatically switch to gas. This keeps the petrol injection system lubricated.
LPG has lower specific energy than petrol so you will get somewhat lower mpg (10-15%) and the engine will develop slightly less power.
LPG burns hotter than petrol but any vehicle manufactured in the last 15 years or so will have hardened valve seats so there should be no problem with valve seat recession.
Much depends on your annual mileage. If you cover a lot of miles, say 15k+ km then you can make substantial fuel cost savings. At lower annual mileages it becomes hard to justify the installation costs and extra inspection and service costs.