Well, I really need to clean my guitar throughly for once (I only use to just give it a wipe with a cloth). What should I use to clean the strings, the fretboard/neck, and the body?

gibson have some products 4 cleaning

they have products 4 clean strings, freatboard, guitars finish and other stuff i dont remember

go to gibson.com or search on google guitar cleaning products
For the fretboard, I use lemon oil/any basic fretboard cleaner. I've never used a string cleaner before... if they're dirty, I change 'em. For the body of the guitar, there's polish you can pick up or lighter fluid works (Don't douse it, just a little bit). For the back of the neck, if it's polished I'm pretty sure you can use whatever you used to clean the body.
An open mind never knows too much.