A good quality low powered (1-4X or similar) illuminated scope is better than any iron sight under any condition (IMHO), If you try this setup you will never go back to iron sights.
That being said, setting up a 336 is a little tricky. The mounting holes are too far back (compared to most bolt guns) so you may need an extension base of some kind. This is especially true with many of the newer scopes, which have long eye reliefs (3-1/2 - 4 inches) for use with heavier recoiling rifles. Also, the stock has a very low comb (it's of course set up for the iron sights) so you really want the scope as low as possible to get a good cheek weld.
I just acquired the Warne 997, it;s an extension base but is also very low (unlike some of the other alloy bases). There is a steel 2 piece equivalent if you don't like alloy.
As far as scope choices I prefer anything without a front bell (ie, straight tube at the front). This will eliminate interference with the rear sight.
