I have a large cemetery I'm working on currently and I'm finding that there are ways to section it off so that I'm only working on a small part at a time. For example, I started off at the mausoleum area where my Uncle is interred, and worked on just the wall where he is - then I worked my way around the corner - and finally to the last 2 walls until I had circled the small area where his mausoleum building is located. I am trying to be thorough, so each person I log I go through and research their source records, parents, spouses, children (if also passed away), and then try to connect them to the tree. It's time consuming, but very satisfying to know that when I'm done that person has been honored by a properly sourced connection to the global family tree and I've found a whole new branch of cousins.
To me, it's not about the size, but the quality that counts. I may never make it through the 75,000+ interments at their location, but I figure that if I work on them one at a time, I'll slowly work my way through it.
And the suggestion above (or perhaps below...)? Perfect. One photo at a time. One record at a time. One area or section at a time. Document everything you can. And record it to WikiTree as soon as you can after the information is documented or else you can easily misplace it or forget details.