Ohkay.. I am a passive member here on PDF. just logging in to help you, cause m from North India (Chandigarh ) myself, and an active traveller.
So, first of all, do bring warm clothes with you, cause places you mentioned have sub degree temp. these days.
Now, if you are going with family, your list is somewhat okay,,
but if you are alone or with frnds then these places gonna bore you.
So, accd to me ur plan should be..
IF WITH FAMILY >>> kolkata>> delhi >>chandigarh >> shimla (kufri is must, just 13 kms frm shimla )>> kullu manali>> dalhousie >>khajjiar ( called as the Mini Switzerland of India, really bful place, probably best, a must go ) >> Amritsar (you dont want to miss Golden Temple, seriously )>> Jodhpur >> Udaipur >>Ajmer (must go ) >>Jaipur>>Agra >>Delhi.
ALONE OR WITH FRNDS >>> kolkata >> delhi >> chandigarh >> shimla (kufri, NARKANDA )>> MCLEOD GANJ (called as little lhasa, tibetans in exile lives there, my fav place in himachal, A must go ) >>kullu >> kasol and parvati valley ( just 40 km from kullu, a heavenly place ) >> manali (rohtang iff the route is open and sohlang ) >> dalhousie >> khajjiar >> amritsar ( wagha border )>> jodhpur >>. udaipur >> ajmer >> jaipur >> agra >> delhi.
P.S. the places I added are just according to your plan. I have not made big changes. however these places are actually better then the overrated shimla manali.
And do keep in mind its really cold out here in hill stations with very frequent snowfall. plan accordingly.
Hope you have a nice trip.
\m/ peace out.