"What would you do if you booked out VFR and then flew most of the trip in IMC conditions?"
Insufficient data. Which Class of airspace, which country, what pilot qualifications......
If you find that you are unable to maintain VMC, advise an appropriate ATCC in good time, then use the privileges of whatever instrument qualification you hold until you can regain VMC. Take a RAS if you're inexperienced, and follow ATC advice. Otherwise you may prefer to take a RIS if you're capable of flying, thinking and communicating simultaneously.
If you blunder into IMC without any qualifications - good luck. You'll certainly need it.