The gemara tells the story of the daughter of Nechunia who would dig wells for the olei regel to have drinking water on their way up to Yerushalaim. One day she fell into a well and people feared that she was killed but R' Chanina Ben Dosa was sure that she was alive because the zechus of her father doing mitzvos with the wells protected her. When she was asked how she escaped, she said that an old man who rashi identifies as Avrohom Avinu came with a ram symbolizing the akeidas yizchok, and rescued her. Why Avrohom?
In Chagiga 3a the gemara says darshens from the pasuk מה יפו פעמיך בנעלים בת נדיב - how beautiful are the feet of the Jewish people when they ascend for aliya l'regel. "Bas nediv" refers to the daughters of Avrohom Avinu who was the first convert. Rashi explains that the concept of Avrohom being the first convert meant that he devoted himself entirely to recognize Hashem (it does not mean that he had the status of a Jew, because Rashi writes in avoda zara 3a that he had status of a ben noach). Once again we see a connection between Avrohom and aliya l'regel, but now with some insight that Avrohom devoted his entire self to recognize Hashem. The gemara in Pesachim 8b comments that when the Jews go to be o'leh regel Hashem offers special protection to their possessions and property which would otherwise be ransacked by the goyim who all know that the Jews leave at that time of year to be o'leh regel.
Avrohom Avinu symbolized giving up all worldly possessions, leaving his father's home and even sacrificing his own son, in pursuit of Hashem's will. He was literally on the go, trusting in Hashem's protection. It is Avrohom who gave the courage to klal yisroel to be o'leh regel 3 times a year, placing the protection of all their physical possessions in the hands of Hashem. Nechunia who enabled people to be o'leh regel by digging wells to provide drinking water, was protected by Avrohom since the aliya l'regel demonstrates the character trait of mesiras nefesh that Avrohom instilled in Klal Yisroel.