Klineline doesnt close the gate until summer time, so I dont think you'll have any problems with getting in early, Battleground I do believe has a live in ranger, who can ticket you if you are in there before 8am.

I checked Washingtonlakes.com again, and I see a post about a 100$ ticket if the ranger catches you on the water before 8. Have not heard if they will allow earlier than that or not. I doubt it since it is a year round lake and doesnt have an "opener". Call the "Tackle-Box"(360-687-4441)7704 Northeast 219th Street Battle Ground, WA 98604
They can tell you the most up to the minute news. Also remember that if you have a boat, no gas motors are allowed. Electric or row only. Enjoy and good luck!