Hi there, I am from Jaipur and as it;s my home town, I can assist with this. A road trip from Delhi to Agra and whole Rajasthan is very popular and these are the sites and cities which you should explore.
Day 1 - Leave for Agra from Delhi via Yamuna expressway. There is a toll of Rs 400 which si quite high but it's worthy as you will reach Agra in three hours. On the same day you should visit Agra Fort and Akbar's tomb.
Day 2 - Reach Taj Mahal by morning and Fatehpur Sikri by evening and on the same day reach Jaipur. On the way you should definitely visit Chand Baori Stepwell. Here is a picture:
Day 3 - Go for a one day sightseeing tour of Jaipur where you can visit Amber fort, Jal Mahal, Birla temple, City palace, Hawa Mahal and Jantar Mantar. If you are not tired, then visit Chokhi Dhani by evening.
Day 4 - Reach Ajmer by 12 noon and spend the whole day here by visiting Ajmer sharif dargah, Adhai Din Ka Jhonpra and evenng walk at Ana Sagar Lake.
Day 5 - Reach Jodhpur by night via a stop at Pushkar.
Day 6 - Full day sightseeing tour of Jodhpur where you should see Mehrangarh Fort, Jaswant Thada, Unaid Bhawan Palace and Mandore gardens.
Day 7 - Reach Jaisalmer by night and stop at Ramdevara temple.
Day 8 - Full day sightseeing tour of Jaisalmer.
Day 9 - Half day sightseeing tour and reach the sam sand dune by evening.
Day 10 - Reach Udaipur.
Day 11 - Full day sightseeing tour of Udaipur.
Day 12 & 13 - Reach Bikaner and spend a whole day for sightseeing.
Day 14 - Come back to Delhi.
For the list of tourist sites in above cities, check lonely planet. tripadvisor India and Santram Holidays websites.
Hope I was able to assist.