Get a front basket, you will use it all the time.
Get a half front windshield...works great to help keep the wind out of your face, but also works great as a place to rest your gun to shoot.
A gun rack...I bought a bar that comes off the A-frame and mounted some gun grips, and put another set on the back that holds my shooting sticks.
I don't have any light bars yet, but that's my next addition.
Picture of my Bad Boy Ambush...it's a gas/electric combo, and is great for stalking pigs at night in silence: