The received wisdom is that Rajasthan is hard with small children. Long drives, hot afternoons, a lot of standing in forts listening to dates. Most of that is true if you run an adult itinerary at adult pace.
What worked for the Nair family in February: no drive longer than four hours, hotels with pools, and one fort a day rather than three. We moved the Amber Fort visit to opening time so the elephant courtyard was empty and it was still cool, then everyone went back to the hotel until four.
The desert was the surprise
The camel ride lasted twenty minutes before boredom set in, which we expected. The camp afterwards was the hit — the dunes are a two-storey sandpit, the folk musicians let children hold the instruments, and the sky at Sam in February has no light pollution at all.
What we would cut next time
Jantar Mantar. It is a remarkable place and it means nothing whatsoever to a four-year-old. Use the hour for the bazaar instead.
