We stayed at Graeme and Lana's campsite for two nights. The cabin was basic but comfortable, although our cabin backed onto the kitchen and we found it was a bit noisy (6:30am) early in the morning.
Graeme was very welcoming when we arrived and showed us around the campsite. The camp kitchen had plenty of fridge space and supplied all cooking equipment, crockery and cutlery.
Wifi was available in the kitchen but we could not get a signal in the cabin.
The shower block was clean and although there are only 2 showers per gender, but only had to queue for short time.
Charleston is a small quiet place but it is well worth a walk down to the beach for the amazing sunset and to enjoy the short coastal walk. Westport is nearest town, 20 mins drive (supermarket/ eateries/pharmacy). Also a good base for visiting the Seal colony at Tauranga bay and Carter's beach which has black sand.
Overall I would recommend staying at Graeme and Lana's camp site, we found it a fine stopover on our drive up the west coast.