I'll post what I do, because it seems radically different to most Apple users
Coming from an an Android background, where there is no such thing as an iTunes or iCloud backup & where to restore a device you need to do things manually having first remembered to create backups of your own data (photos, documents etc) first means that I look at things differently.
I am fully post PC & have no laptop or desktop computer to use iTunes on. Therefore all my backups are done via iCloud. Now, in my mind there is no need to back up all the apps I use - thereby creating very large backups that will soon get bigger than the free space allowed as the App Store remembers all the apps I have used or bought and allows a free reinstall of them if I need to. My backups are therefore restricted to my browser app for its bookmarks & any games I play in order not to loose the progress I have in them.
When it comes to photos, IMO the Camera Roll is a poorly coded joke. It doesn't use long file names & is not flexible enough for my needs. All my documents, photos & home movies are stored on my NAS & I use the app FileBrowser to access them & view them streamed from my NAS drive. Using that app I can categorise documents, PDFs, e books, photos etc on the NAS & if I wish to have a selection of them on my iPad I can copy them into the FileBrowser app, locally on my iPad, into a nice folder structure that matches my convenience.
All my e-books are stored in this way, categorised as I want them. I can open them in iBooks, read them & then delete them from iBooks when I have read them. They are available to be reopened at any time.
All my photos are stored in this way, too. As are my home videos.
FileBrowser allows direct viewing of jpgs, mp4s, PDFs, docs - pretty much any file format that iOS recognises. In addition it allows direct copying of any photos I may wish to place there into the Camera Roll - or the other way round should I ave taken any photos using the iPad.
In other words, rather than replying on Apple and their iCloud for large quantities of data that will take quite a while to upload & restore when necessary, I created my own personal cloud storage that is only accessible by our household & which is quick to access as it does so at the maximum speed of the wifi connection, somewhere around 62mbs.
Hope this helps the OP & others to consider alternative methods that are both inexpensive, reliable, fast & cross platform friendly. A simple external HDD can cost as little as $50 & would give you 500gb of personal cloud storage. For a little more money you could have terabytes of space. Organised as you wish & accessible to any device connected to your router.
You can read lots of help on NAS & the iPad, here...
Network Attached Storage (NAS)