for right now, go on a day trip with everything you think you'll be bringing including water. see if you feel like death after one day. try setting things up in the middle of the day and see what you've used and what you haven't. figure on sunsets, so grad filters aren't a bad idea, hdr can be tricky on moving things. the tripod should be a light one that can fit in the bag. a crook will know what a photo bag looks like, even in the shape of a back pack, you should have a pack that looks like a normal bag. and the tripod should be hidden or everyone will know you have gear in there.
you'll only know what you don't need if you don't ever use that stuff.
you'll want:
camera, duh
batteries (at least 3 sets), i have 2 with a redundant backup. and more in the car or hotel.
a single lens that i use for everything.
you'll want a spare camera, even if it's a pocket camera. the body or lens can break and you'll be... annoyed.
i tripod is nice, but clumsy to use almost everywhere. a monopod may be a better bet unless it's a real long exposure.
cleaning stuff, extra cards and or a backup device.
if you have filters and you don't have a magnetic rim attached, filter wrenches can save your day (i had two fuse), use a rubber band for more grip.
if you have a flash, bring one. if you need instructions, download them to your phone. if you have a phone, try to map out where you are with a trace, so you can figure out what you shot when your home.
a polarizer is good for everything but sunsets and inside.
if you know you'll be at the beach, being a UV filter to protect the lens. an extra lens cap as well, they get lost easy. i use a hood so no worries for me.
i always bring extra padding material and some industrial thread with needles in case my bag needs a repair (in the hotel). i have a few keyring loops on my bag incase a zipper pull breaks off. i always have paracord, it can be used as a quick shoelace and it's used for emergency stuff.
always have water and a snack, i always carry some first aid stuff. along with bug stuff, hornet, mosquitto wipes, and some rescue gear. like a whistle, mirror, and such.
mostly you don't want to look like a tourist, or as little as possible.
---Mike Savad