s1. It's a good house to live in.
I think that in s1 'in' must not be omitted.
s2. It's a good place to live in.
s3. It's a good place to live.
In this sense, s2 is correct but I sometimes see sentences like s3.
I think some nouns can be used like this.
But I don't know specifically what kind of nouns including place can be used like this.
s4. There are many good places to [go / go to]?
Which one is correct? If both are correct, under what circumstance can both be correct?
You could use either. There's no real difference.s4. There are many good places to [go / go to]?