My car: Toyota Camry 1994 LE, 4 cyl, 4 door sedan. Is it possible to install a key less remote access system?
If the vehicle has power door locks it's not a big deal. You can use a system like the one below.
If you don't have factory power locks it gets more complicated. You will need to install door lock actuators, either aftermarket or factory. You could get the actuators, linkages and such from a junk yard, sometimes easier than making the universal ones work. Here is an example of the universal kits
You'll need one for each door and will have to wire them all together correctly.