In Mahabharata, Pandavas used to visit Sudra's homes. It can be clarified from the following passage
Vaisampayana said, 'Then all the citizens (of Varanavata) on hearing that the son of Pandu had come, were filled with joy at the tidings, speedily came out of Varanavata, in vehicles of various kinds numbering by thousands, taking with them every auspicious article as directed by the Sastras, for receiving those foremost of men. And the people of Varanavata, approaching the sons of Kunti blessed them by uttering the Jaya and stood surrounding them. That tiger among men, viz., the virtuous Yudhishthira thus surrounded by them looked resplendent like him having the thunderbolt in his hands (viz., Indra) in the midst of the celestials. And those sinless ones, welcomed by the citizens and welcoming the citizens in return, then entered the populous town of Varanavata decked with every ornament. Entering the town those heroes first went, O monarch, to the abodes of Brahmanas engaged in their proper duties. Those foremost of men then went to the abodes of the officials of the town, and then of the Sutas and the Vaisyas and then to those of even the Sudras, O bull of Bharata's race, thus adored by the citizens, the Pandavas at last went with Purochana going before them, to the palace that had been built for them, Purochana then began to place before them food and drink and beds and carpets, all of the first and most agreeable order. The Pandavas attired in costly robes, continued to live there, adored by Purochana and the people having their homes in Varanavata.
Are there any such instances where Krishna visited Sudra's home or touching a Sudra?