Most recommendable places to travel. There are both express and mail trains from major cities to Hyderabad. There are lot of tourist buses too.
There are a number of places you can see and enjoy here. For instance Golconda forte. Or if you are more of a sea lover you will love hussain Sagar Lake. The lake is a place for good relaxation. Also good for traveling with your family. The most attractive are the multiplexes where you have the biggest 3dmovies to see.
You have a number of cheap hotels as afar as accommodation is concerned.
On the whole a good journey. By the way mind the local dialect of Hyderabad. They speak non native language also but very rarely.
Enjoy your journey a great place for you and your family!