A couple suggestions I have are a little bit safer places to park for free. And clean shower areas. I found a great place to park along the road in Punaluu as well as a clean outdoor shower at the park in Ahupuaʻa ʻO Kahana State Park.
I also think that it would beneficial for you to inform guests ahead of time that they need to provide a cash deposit rather than a credit card number.
The a/c on the van, only has one speed, if you try to turn it down it shuts off completely.
There was old stagnant smelly water in the cooler fridge thing, so I could not use it during my stay. Please make sure all amenities are prepared, clean, and ready for your guests before arrival.
Make sure to ask cost of additional rentals up front.
Overall I would not rent again with VanGo but I would do van life on the island again. I loved the freedom it gave and opportunity to explore the more unique places that typical tourists can’t go.