Is there any content after school trip? And how can i complete student ID and construction worker quests?
Student ID and Construction worker ones are not finished and are still WIP I believe.
I had the same issue you did not knowing what to do after the school trip. Since I asked this is what's been posted on Patreon:
Here is a short guide how to navigate through the Free Roam for 0.6.11
If you've finished the camp events and have returned to the city there should be a small event where you get to talk to miss. Kazuki inside the classroom, the first time you interact with her, she will act like she has always treated you before camp. After that, you have to wait until it is in the afternoon, go to the third floor and you will see her in the corridors but only if you haven't interacted with anyone else, an event will trigger(she will get secretly groped by Takeshi while she is being consulted by 2 female students) if you talk to her and that is event 1 Free Roam for miss Kazuki, at this point you cannot interact with anyone else as you've used up your interaction "tokens" for the day.
Event two should occur once you talk to her again the next day. (your "tokens" get recharged everytime you sleep in your bed.)
She will be called to the principals office to discuss a certain matter with the principal. She will end up talking to Takeshi about it.
For Satoshi, you can start his 1 event chain after doing 1 event with miss Kazuki first. you just need to interact with him in the morning first priority. (He ends up contacting A mystery person.)
Same goes for Shizuru, you can start her 1 event chain after doing 1 event with miss Kazuki first. (She invites Takeshi for dinner at her place.)
After that you have finished the FREE ROAM, congratulations.
Since there's no more persons and events to interact with, YES you cannot sleep anymore on your bed because you basically need to have used up at least one "token" to do so.