I would suggest The Golden Triangle Delhi-Agra-Jaipur. Besides that, you can also go to Shimla, Manali, and Chandigarh. I have been there before, in December 2008 and I'll go again at the end of this May. Although it'll be too hot during that time, but it is worth it. If you have any questions, feel free to ask me.
Well recently i was in India .....and there are many places that you should not skip....
the shortest itinerary is the Golden Triangle (Delhi-Jaipur-Agra) which is just a glimpse of India... If you are looking forward to know India better and to feel the culture.. then you should not skip Rajasthan, coz the culture lies there .... though it wud hot during April but still Rajasthan is one of the state of India tht shows the clear picture of India as you have seen in your dream.... people in colorful outfits, men wearing Turban, camels, cows, busy streets, ages old forst and palaces, roadside Bazaar and a lot more....
You can note down the places that you shud visit :
Delhi - Qutub minar, Humayu's Tomb, India Gate, President's House, Lotus Temple and more
Jaipur - The pink city, here you can enjoy the elephant ride while going towards the Amber fort, apart from that you can see places like Water palace, City Palace , Observatory, Wind Palace, Birla Temple, Monkey Temple (World famous monkey also a part of a documentary "Monkey Thief's" on National Geographic and lots more.
Mandawa : you can visit Mandawa Castle and the Haveli's
bikaner : Camel Farm and Karni mata Temple (Rat Temple)
jaisalmer: Enjoy camel Safari on Desert and and see the village life as well..
jodhpur : The Blue city here you can visit the great Mehran Garh Fort, Jaswant Thada, Clock Tower and can experience the village life as well
udaipur : The Lake city, beautiful city of Rajasthan having lots of lakes... beautiful Forts and palaces... one of the best.
pushkar : Holy Place of Hindu.. here you can visit the Brahma (hindu God ) Temple the one and only temple in the world.
Ranthambhore : can visit Indian Tiger National Park
Abhaneri : Where you can experience The great Step well of India (Chand Bawori)
Agra : Place know for the first wonder of the world " The Taj Mahal" and can also visit Agra Fort
orcha : Visit Temples and Hermits staying there ....
Khajuraho : Interesting place Known for Khajuraho Temple.... having sculptures of Kaamasutra...
Varanasi: Totally different place.... one should visit this place once in life.... very powerful place..... religious center of Hinduism... here you can have boat ride (River Ganges) and can experience the evening ceremony.... and can experience hindu cremation ceremony at riverside.... and can enjoy the rikshaw ride in the busy streets.. moreover you can visit the near by places.... like Saartnath (Buddhist pilgrimage place)
My friend from India suggested me this itinerary and trust me i had fun..... If you need any help regarding your tour.... you can take his help.... he is a genius... he knows almost everything at such a young age.... almost everything about this huge country... trust you will be amazed to meet him and his great family... we also met his family on dinner .... such a nice family..... and her cooks well!
If you want you can talk to him he will tell you every thing..... [snip]
I hope this will help you !!
Have a nice Journey!
[ Edit: Sorry, no personal details please. ]