While in Rajgir the wealthy businessman Anathapindika first met the Buddha and invited him to come to Savatthi. The Buddha said he would be happy to come but asked that suitable accommodation be provided.
When Anathapindika returned to Savatthi he purchased a park near the town and built a large monastery on in. Called Jetavana, this park became the Buddha's favourite resort and he spent every rainy season of the last 20 years of his life except one there.
Today the ruins of Jetavana's many monasteries are set in attractive and peaceful gardens. The Buddha delivered more discourses here than in any other place so if you wish to read some while you are you have plenty to choose from. I recommend the Kakacupama Sutta, the Vimamsaka Sutta and or the Angulimala Sutta, all of them from The Middle Length Discourses.
There are plenty of Buddhist temples near the ruins that offer accommodation. Perhaps the best is the Sri Lankan temple right next to the main gate. Don't miss the paintings in the main shrine (see above).
If you do not intend to go on to Sankassya you can take a bus or vehicle from Savatthi to Lucknow and from there get the train to Delhi. If you have the time visit the State Museum in Lucknow which is in the grounds of the zoo. It has an excellent collection of Buddhist sculpture and is open from 10:30 am to 4:30 pm and closed on Monday.