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.
Yes, but the amount of effort and money depends on if it has power door locks, and if it's a manual or automatic transmission.
It would be possible, but as Brian Knoblauuch has pointed out it would not be a viable undertaking. The cost would probably be greater then another vehicle of the same age with remote key access on board.