nerfhaven is mostly for getting more performance from the darters, not so much for aesthetics.
as far as wooden handles go, the triggers usually go almost completely to the rear of the grip area, so you have to plan well to keep it all working.
every one that I have ever done, I swore to never try the same gun again. if you don't plan enough ahead, I guarantee you will spend 3 times longer than you hoped for, and will probably do it over at least twice.
you could go with a completely fake barrel above the real barrel and leave the real barrel to mimic the feed tube like on a pump shotgun. I used a recorder (plastic flute/whistle) for a fake barrel and made it look like a tommy gun. same gun I used the epoxy putty to build up the hand grip below the trigger and painted it like wood, it looks more like wood than the real wood I used to make the front grip.
a giant water barrel in top of everything and maybe a shoulder stock would definitely hide the nerf pretty good, it would have a nice video game vibe to it too.