I've also thought about this, providing it would work within 12-14 days:
Delhi - Shimla - Mandi - Dharamsala/Mcleod Ganj - Amritsar - (i assume via delhi) - Agra - back to Delhi to fly home.
thanks so much, i think that sounds like a good route to go with, just need to connect the dots with trains and find a good driver now, i think we might prefer that to bus! We are thinking of 2nd-15th november, would this be a problem right after Diwali and with the toy train, would there be a better month to consider? Other times we could potentially go are september or sometime between march and june?