21 days are good enough to travel all the places mentioned however little hectic. Delhi-Leh- Delhi is the best way to plan Leh and you should keep at least 5 nights for Leh.
Delhi to Amritsar can be done using flights but you would not get any direct flight from Amritsar to Leh. If you want to include Leh then i would suggest you to do it first from Delhi using flights and then start your journey onwards Agra and Rajasthan. For Agra and places outlined Rajasthan, 1-2 days overnight stay is sufficient.
2 days are good for Jaisalmer, Udaipur, Jaipur, Jodhpur. 1 day stay is enough for Bikaner, Agra.
Plan is bit hectic but very much doable.
let me know if you have more queries.
Thank you so much for your input, really helpful for a first timer to India.
I wish to cross off one destination so it won't be hectic, do you reckon I skip Jaipur or Jodhpur?
Also, I read that only 1 hotel is open in Leh during winter and I have to do home stay. How do I arrange a home stay as I do not wish to stay in the hotel?
I do not think there is a need to skip Jaipur or Jodhpur. If you want then exclude Bikaner as its little off the tourist trail. Given the time window you have i think you can easily cover places you shortlisted.
Most of the hotels remain closed during winters but still you can find handful of options. I think at least 3-4 hotels remain open. you can get it once you are in Leh. Homestays are also available and you can get those once you are in Leh. you can not book those in advance. No need to worry about accommodation in Leh. you will definitely find it.
Thank you so much Vishnu, very much appreciated.
Now I can start planning my itinerary, do you reckon I can just go to India without pre-booking accommodation and transportation or would you suggest me booking them in advance?
Many thanks again.
Sorry for late response. There is no need to book hotels in advance. you can easily get accommodation once you are here.
Can you please let me know which is the harvesting and plucking season for apples.
Also please advice on Dalhousie - Khajjiar - Dharamshala - McLeodganj trip
Apple season is August-September-October. at some places its little early and sometimes little late.
Dharmshala, Khajjar, Dalhousie and Mcleodgunj can be done in a single trip in 5-6 days.
Thank you for taking time to reply, you've been really helpful. :-)
Glad to hear that i was helpful. Wish you happy tripping in India.
21 Days are enough to explore these places in North India but you should keep Varanasi in your Itinerary too as it is the most important part of North India.
Thanks for adding your comment, Alina. 21 days would be little tight if someone wants to visit all of Rajasthan, Uttar Pradesh and Madhya Pradesh but highlights can be easily covered. Varanasi is indeed something not to missed.