Since most of the commentary in BoLT is CT comparing that with the Published Sil, and the later versions his father wrote... remarks about what stayed, and what was abandoned and how one thing stayed but was changed due to coming about some other way or happening with another character, and in most cases you probably will have noticed these on your own, I would say you can skip the commentary except in cases where the chapter contained something that makes you wonder what CT has to say about it.
The notes are more tidious and mostly point out changes
Tolkien made to the manuscripts... usually name changes, and unless you care about such things you can just avoid them.
I'd say, simply put: If it doesn't interest you, don't read it.
What I would not recommend anyone skip over though, is the narrative intro to the
tales.... that writing with
Eriol, Rumil and Lindo is some truly great stuff.
And later on if you look at the
books in a different way and the commentary and notes become of importance to you, you can always read them then.
Well , I obviously agree with baragund... but figured two opinions would be stronger than one.