Re: Lake Hopatcong, NJ State Park...
I live in Lake Hopatcong. I've used Lee's a bunch of times when I had a wave runner. They have 3 launch ramps and plenty of parking located in Mount Arlington. They leave around 6 or 7pm. It's on the honor system to pay after hours in a drop box. You can stay out all night and day. You check in at the gate and they take down your plate number, same for after hours drop box form.
The State Park is located in Hopatcong and the ramp is free. It's a long narrow ramp and heavily patrolled / monitored by police. Just make sure everything is legit, all trailer lights working, proper chains, reg, cleaned hull, etc. I never launched from there but have seen it busy when I was out on the lake.