After stripping a couple of 3 frames with equivalent rust, I would not be concerned too much, but concerned to some degree, not being able to see what is under the paint. Look here for an example. I really dont' what to add a lot of pics!
https://www.flickr.com/photos/112094...7638854295965/
Before removal:
After:
I was surprised at the amount of rust runners that were not detectable prior to stripping. I am glad I did. I did not find any rust throughs but some of the pits were good to expose. What I see in your pictures are equivalent to what I found on this frame.