How many days do you have for the tour?
Just about anyone (including my polio self) can do 60 miles (100 km) in a day, so long as there aren't too many hills and there isn't a bad headwind. Rain will slow you down (and can make the ride miserable) but won't stop you unless it's very heavy or the weather is especially cold. (Hail, on the other hand, can stop you.)
100 miles a day (160 km) is reasonable for someone who is fairly well trained, if the weather and hills cooperate. And most people who aren't quite so well trained can do that distance "unreasonably" if pressed.
Hydration isn't necessarily a big deal. You should have at least two 16 oz water bottles (readily accessible), which you fill several times a day. You don't need more unless you'll be far from civilization or riding in unusually hot conditions. Drink before you're thirsty. Get in the habit of taking a swig every 10 minutes or so.
For maintenance you need mainly tire repair tools and a multi-purpose tool made for bikes. For first aid a few Band-Aids, some antibiotic ointment, maybe some gauze and tape. And your water bottle (for washing off wounds). Your likely injuries are minor cuts from sharp edges of the bike plus "road rash". Also have sun lotion and bug spray. And some hydrocortisone ointment is nice to have for bug bites and "butt burn".
Precautions: Wear a helmet!!!
Nothing wrong with that bike, for such a short trip. Just keep the tires inflated to the max sidewall pressure. If you were biking across the US you might want something different.