It is good to have guide in each city. guide will give you the info for monument and city it is not only about history it is also what to do and what not to do in monuments,Temples,Mosque. or with local people. do not trust on drivers only they have limited thinking. my advice is to hire a guide for full or half day in each city.
these are some places if you like something from these so you can add in your program or else ignore it.
Places to visit :
Delhi : ..Qutub Minar, Jama Masjid, Humayum Tomb, Lotus temple. India Gate, Akshardham Temple.
Agra: ...Taj mahal, Agra fort, Fatehpur sikri, Itmad ud dula ( Baby taj ), Sikandra, Mehtab Garden(at back of Taj mahal.)
Jaipur:... Amber fort, Hawa Mahal, Janter manter, City palace, Jal mahal, Chowki dani.
Ranthambore: wild life.
Jodhpur : Meran gardh fort, Jaswant tada,masala market cloack tower, mandor garden.
udaipur: City palace, boat ride, princess garden, sanjan garh(mansingh fort).
Jaisalmer : Sonara kila, sand dunes camel ride.
Bikaner: juna garh fort ,karni mata temple( mouse temple) .
Important notice Taj mahal is closed on every FIRDAY.