Hmm .. that journey is surely more than just a weekend trip ?
There are direct trains but no direct flights for this journey. kolkata (West Bengal) to Udaipur (Rajasthan) distance is 1823 km and you can get there by flight + flight in just over 6 hours and 50 minutes or by train fares starting from ₹ 591.
Avoid the sun and have cold drinks to escape the heat.