As you may already know, trigger flop is common with Marlins. A four pound trigger pull doesn't sound bad to me. I like a crisp trigger pull, the flop just goes with the territory.
I've heard mixed reviews on the Happy Triggers. Most seem to love them though. It sounds like a decent upgrade, but they don't give them away.
A straight stocked 35 Remington from 1963 sounds like a perfect woods Gun to me!