I think you are doing great. It was just the missing roads that drew my attention.  And I'm glad to see another park ranger updating OSM. I've been in contact with WA Parks and Rec over the years. Mainly with adding park boundaries. Yours wasn't one of them. 

It appears from the bing imagery that there is still a road into the parking  area at the southeast end of the park (next to a restroom). The imagery isn't real clear at the northeast end. Bing seems to show the service road block off, but the new maxar and NAIP imagery it isn't clear.

I'm happy to add the service road back in but you have the local knowledge - which I respect.