Vancouver Lake Park and the nearby connected wildlife refuge are great places, but keep in mind that the wildlife refuge is a popular place for hunters during certain times of the year. If you go out there, be sure to wear some bright clothing or some other item that can be visible. Don't go down some narrow little trail through the brush where people can't see you.
The hunters seem to all have a protocal that keeps them from shooting at eachother, and they all seem to wear camiflauge clothing that make it very difficult to see them. However, unless you understand what is going on and where it is going on, it is best to make sure you are visible and not something to shoot at.
I have lived in Vancouver for about 13 years of my life and I know the only warning you need is, DON'T GO THERE! I have already walked down that path and I want to save some people from making the same mistake I did. So if you find yourself in a car bound for Vancouver, Jump Out!