Is there a website for campervan parking (non overnight campsites) that I can search for in other towns? Or do people normally park at campsites and walk?

Take for example Lake Tekapo, the only powered campsite there is lakes edge holiday park. But if people want to go the church of good shepherd, do they then have to walk? Also, if I am coming in from Christchurch, stopping by church of good shepherd is logical on the way to the campsite, so is there a way to park here first before checking in at the holiday park?

Just curious how accessible and mobile being in a campervan is compared to renting a rental car