Then they continued the yagna, which got completed, and Rama resumed his royal duties. I would guess Kush & Luv were taken care of by, in addition to Rama, the rest of the family - Kaushalya, Urmila, et al and had their cousins as companions for a while.
Years later, the 3 rajmatas died, surrounded by their sons and grandsons. After that, Budhajit, the ruler of Kekaya, suggested to Rama that he conquer Gandhara. Accordingly, Rama sent Bharat along with his sons Taksha & Pushkal, and they invaded Gandhara. After 7 days of intense fighting, the Gandharvas were defeated, and that land was conquered. Two capital cities were built - Takshashila (today's Rawalpindi) for Taksha and Pushkaravati (today's Jalalabad) for Pushkal. After 5 years of helping them establish their rule, Bharat returned to Ayodhya.
Rama then expressed his desire to enthrone Lakshman's sons as well and asked Bharat for suggestions on where to enthrone them, and Bharat suggested Karupadhadesh, on the foothills of the Himalayas. Accordingly, Rama, Lakshman and the latter's 2 sons Chandraketu and Angad invaded Karupadhadesh and conquered it. A city called Chandrakant was founded for Chandraketu and a city called Angadvad was founded for Angad. Once they were crowned kings, Lakshman stayed with them for a year and after that, returned to Ayodhya.
After that, the incident with Kaal-deva and Durvasa took place, resulting in Rama having to disown Lakshman and Lakshman giving up his life in an yogic trance near the Sarayu (today's Lakshman ghat in Ayodhya). Although Rama had disowned him, he was saddened and decided to follow him, and asked Bharat to take over. Bharat refused, and instead suggested that Kosala and Dakshin Kosala be handed over to Kush and Luv. Those 2 were crowned, and Shatrughan was also informed of Lakshman's passing, and Rama's decision to leave for swarga. He then crowned his sons Subahu and Shatrughatee the rulers of Mathura and Vidisha, and then returned to Ayodhya. Then Rama, Bharat, Shatrughan, Sumantra, Janak, Sugriv, Guha, et al all headed for Vaikuntha along with their followers, while others like Hanuman, Jambavan, Vibhishan, were left behind. Also, Angad (Vali's son, not Lakshman's) was crowned king at Kishkindha.
Once all this was done, Rama, Bharat and Shatrughan returned to Vaikuntha in their mortal body, while the rest of them cast off their bodies in the Sarayu and then boarded the pushpak viman, and went to swarga. Sugriv returned to the abode of Surya.
Edited by Chandraketu - 16 years ago