Not too bad, I think it will look pretty good after some rust blue. Enough rust on it already to get a good start.
I have done quickie jobs on guns like that by blasting the parts with fine aluminum oxide (150 grit), followed by rust bluing. A fine grit like that will clean off the remaining rust and give the bluing a good bite, and the blasted texture is so fine that it will disappear after rusting and carding.
Here is one I did that way: