My girlfriend and I visited here as part of our NZ tour. Really there is very little to do in Alexandra other than the Otago Central Rail Trail which we were there for. We chose this place as it was the only listed campervan park in the town in the free Jason's guide we had, though we now realise there was another park nearby...oh how we wish we had gone there.
I first started to feel weird when I met the owner, she was nice but was a little too intrusive about my relationship with my girlfriend, its none of her business if I am married or not. Then we drove into the park, it was like a campervan/caravan graveyard. Honestly, it wouldn't have seemed out of place on The Walking Dead. The buildings had a delapidated scout camp feel about them, all concrete floors and sheet metal doors, I half expected to meet an axe murderer when leaving the showers one night.
It's also weirdly up to date in some places (taps which have no handles and work via touch sensors, automatic doors), which when contrasting it with the dated decor and toilet block which feels like a slaughter house is highly bizarre. To be fair the place was clean, tidy and cheap but its still felt a bit backward and the both of us had a strange sense of 'end of days' about the place.
In conclusion it was cheap and tidy but not exactly comfortable. My suggestion, at least have a look at the other campsite in the town before you come here.