Which party is more conservative?

[Pennsylvania Deplorable]

It depends on how you define conservative. AfD's last campaign was co led by a lesbian. Unlikely to happen in the GOP. On the other hand, AfD runs to the right of the GOP establishment types on issues like immigration. AfD is also split into factions, however, and its more economically left wing faction is to the left of most of the GOP, while the other side is almost full on Rothbard. I guess I would say the GOP because AfD is better described as right wing populist than conservative (a label best bestowed on the CSU and pre-Merkel CDU in Germany)