It is easy. Take an electric train on the Finland Vokzal in S-Petersburg to Vyborg city (near to 3 hours). That is all. By the way, do not miss the Vyborg railway station, because at the next stop after the Vyborg you may be arrested by nice young guys in nice green uniform from russian border guard and may be questioned for all the day about who are you, what are you doing here, what are your real name (Osama ben Laden may be?) and so on... Be careful!
The Castle is seen just from the square near the railway station. You can reach it near to 15-20 min by foot. Annenskie fortifications are located to the north of the Castle 10 min by the foot. For the Batareinaja Hill you should go out railway station building and make a left turn and go near to 20 min.
Pappilaniemi (cape Bobovy): It is need to get to the Koivisto (Primorsk - modern name) road. You should drive over the bridge near to Karemäenlahti bay (Zakrytaja bay), than drive near to 1 km and make a right turn. The artillery position located near to 600-700 meters from this turn.