News are plural so you must use These and are. In my opinion you should use Will not instead of may, because less students is a consequence that Will surely happen and not a possibility. Thirdly, sightseeing is not a place itself, it is a verb (an action) so you need to add the word spot or site or anything that will say it is a location. Good luck and all the best! :D

Most students have been back to school. These news are great to hear, because many places will not be so crowded, such as some sightseeing spots, movie theaters and department stores.