I've a Kindle Voyage - there are fewer options available for it (probably partly because it didn't sell as many units as the PW and partly because the back of it is an odd shape, awkward for stickers/decals) so you might have more choice for your version, but maybe my combo will inspire you. I like my Kindle lightweight and "almost bare", and these are the items I use and am very happy with. The links are all to Amazon UK because that's where I purchased them.
- a Skinomi skin - I've found these to be very good quality:
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
- a hand-strap for security - this is the one I've been using for several years:
https://www.amazon.co.uk/TFY-Securit...ps%2C88&sr=8-1
- a case for storage/travel. I have two. This one is very thin and lightweight:
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
...and this one is thicker but offers more protection, as well as a pocket on the front where I can put my glasses, charging cables, etc:
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
I don't use a screen protector at all (the Voyage has a more robust screen than many other models). I do have screen protectors on the Kindle PWs that my kids have, and they definitely aren't "invisible", but my kids don't seem to mind. They also have their Kindles in cases which have a hand-strap as part of the case - similar to this one:
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1