Well, you should consider bringing some entertainment like a book or a tablet to pass the time. Also, comfortable clothes are a must as you'll be sitting for a long while.
The length of Trip's story in Sonic Superstars can vary. It could take a few hours if you focus mainly on the main quests, but if you want to complete all the side missions and uncover every detail, it might take longer.
First, know your limits. Don't overdo it when it comes to consuming weed. Second, be in a comfortable and familiar environment. If you're in a strange place, it can increase the chances of a bad trip. Third, have positive and trustworthy people around you. They can help calm you down if things start to go wrong.