What mekoros from the rishonim and achronim exist regarding the halacha brought down in the shulchan aruch - that one doesn't have to heed his/her parents' or his/her Rav's wishes regarding certain issues such as marriage with a certain person (assuming there are no halachic issues that would prohibit one to the other)and living in eretz yisrael. Would the same apply to dating? I am looking more for the iyun and mekoros on the topic than for a definitive psak.
I'm not sure what you mean by "dating" as opposed to marriage, since dating is obviously permitted only with matrimonial intent.
As for marriage, the source of the Halachah brought in the Rema is Teshuvos Maharik #176. See also Sedei Chemed, Ma'areches Kaf #147, Meishiv Davar 2:50, Agudas Eizov #16 and Shevet ha'Levi 2:111.
Dov Zupnik