What is the connection between "Pen Yirdof Go'el ha'Dam" and the previous Pasuk?
Rashi: It is written with reference to 'preparing the way' in Pasuk 3 and to the designation of many Arei Miklat in Pasuk 2. 1
Rashbam: It is written with reference to "Veshilashta es G'vul Artz'cha" in Pasuk 3. 2
See Sifsei Chachamim. Perhaps we can add that it also incorporates the additional forty-two Arei Miklat - See Mas'ei Bamidbar, 35:6 & 7. See also Oznayim la'Torah, who explains that the many Arei Milat is meant to confuse the Go'el ha'Dam, who does not know which Ir Miklat the murderer is fleeing to. See Oznayim la'Torah, who elaborates.
To whom is "ve'Lo Ein Mishpat Maves" referring?
Targum Onkelos and Targum Yonasan: It pertains to the murderer, whom the Torah is giving the chance to escape the Go'el ha'Dam, because he did not kill his relative on purpose and is not therefore Chayav Misah. 1
Makos, 10b: It pertains to the Go'el ha'Dam, and teaches us that if he catches up with the fleeing murderer and kills him, he is Patur. 2