Keyser, would you say there are any pros or cons to the order we visit the cities, based on the fact that we'll be arriving into DEL in the afternoon?

Now that I look at a few websites, it seems you can't fly Delhi-Agra, but can fly Delhi-Jaipur. Leads me to think we should think about doing them the opposite order from what I suggested above. Grab bags from our KTM flight, head straight to a Jaipur flight. Spend 2 days Jaipur, take a car or train to Agra for 2 days, then train to Delhi for a few days before departing out of DEL.