The RA motor is very easy and simple to fit. You will have no problems with that.
All it will do is track so you do have to find the objects yourself which is part of the fun (I have always found this more satisfying and you learn the sky better).
When I bought my motor I think it was about Â£80. I got it from Stockport binnocular & telescope.
You will certainly see a vast amount of objects in a 200mm scope. It was not long ago that the average amateur could only hope for an 80mm refractor or 150mm reflector! If you do not have one get youself a good star atlas something like Nortons which also contains lots of info.