The only thing we know is what they sell for new. You are say'n NADA is no good? You want more than NADA high book? $5872. Your addons don't mean a lot.
I own a 2015 850. Bought it new and know what I paid for it. I also know what a dealer would want for your bike, what a dealer would give you for your bike, you a dealer?
You ain't gonna sell it if you can't put a number on it. If the number is too high, you ain't gonna sell it either.
2015 Sportsman 850 in Sage Green
3500 lb. Polaris HD Winch
QSC Clutch Kit (from Ryan @ RVS Performance)
Odyssey PC925L-P Power Sports Battery
VIPair Windshield w/mirrors
HD ATV Gear Billet Pinion Cover
EPI HD Springs, Front & Rear
Cecco Frame Braces
27X9 and 27X11-14 STI Rocktane XD Rubber
Guru Bumpers, Front & Rear
Lock 'n Ride Front & Rear Boxes
Rhino Monster, Rear Box
Camoplast Tatou 4s Track System
Heated Grips and Throttle Control
Lowrance BAJA 540 GPS
SuperATV EZSteer 380
Various Mods for Ice-Fishing