Yes you potentially have a great turkey killer there. You are correct though that the factory stock is probably too long for you. I suggest taking a look at the ATI Akita stock. It is adjustable for length of pull while maintaining a traditional stock appearance. It also has an adjustable cheek pad that can be raised to make shooting an elevated optic sight more comfortable. It is one button adjustment for length of pull making it instantly adjustable for various size people but it locks up solidly.
The 24 inch barrel is a good choice for the gun. It is very versatile and gives great turkey patterns. There are many chokes that shoot well in the 835. Generally .670 to .680 constrictions perform well with the tightest patterns. Some people prefer to use a choke in the .690 range to give a little wider, more forgiving pattern. I have had my best luck with the Indian Creek Choke. Other chokes that have performed well in my gun are Pure Gold and Kicks. Hevi 13 shells perform well, but if you want to stick with lead and save some money on shells, the obvious choice are the new Winchester Long Beard XR shells.
You mention that you want to put an optic on the gun. The sky is the limit on this. I and a lot of people believe the open lens reflex style sight like the Burris Fast Fire is THE way to go on turkey guns. They are extremely accurate and give excellent field of view when shooting with both eyes open. Others go with tube style red dot sights or even scopes. However I do not care for the tunnel vision they cause and a scope on a high recoil shotgun can be downright dangerous for someone not experienced with shooting scopes. The easiest solution and best looking is to mount a Fast Fire to the gun using a Burris Marlin 336 base. It just so happens the base fits the profile of the 835 receiver and the rear mounting holes. It gives a compact, finished appearance.
Lastly, your not going to accessorize the gun with items that exactly match the existing camo. If you truly want to give the gun a factory appearance your going to need to send it off to be dipped in the pattern of your choice. You will need someone who is experienced with stripping the existing finish off and putting a completely new finish on the gun. The name I see come up most often with best reviews for this is Rob Roberts.