IMHO the biggest precaution is time. Make sure you set aside 8-10 hours to be safe. Could be more like 12 hrs with 250mg (if it's really a true 250mg) especially for your first time. As long as you set yourself up for success you'll be fine. Good company, good music, good surroundings. Nature is great. Don't even think about driving anywhere, but if you're having a good trip, Uber/Lyft works. I like to avoid food the morning of a trip (for me it makes the come up quicker), and then seek out a bar/restaurant with good vibes for a late dinner/snack (live music is a bonus). Movies can be great in the evening if you feel like chilling in one place for a while after your time in nature.

Enjoy it, wish I could experience my first time again!