Wow. At least 5 OS's... The most I have ever tried was 2... But, then that was a long time ago, when dual booting on Linux was a bit flakky at times... I was going to say that you must have several hard drives installed but then I remembered that Puppy has a small 'footprint'...
What kind of difficulties have you had with Puppy? I am always looking for a distribution that is the most stable...
I just created a separate partition (ext3 format) on the hard drive - total HDD on this laptop was 250GB so I took 50GB of that for Puppy, and they all install nicely side by side in the same partition. I use the option where each distro had its own "sessions" where the data files and installed programs are saved to their own file (a sfs file, a kind of virtual partition), where I reserve anywhere from 512MB upto 8GB space for a particular "session". Each session has its own separate customizations and data files which you can back up or roll back by simply copying the SFS file. If you run out of space, you can always increase the size of the SFS. You can also share files between sessions by saving them to the parent partition (outside the session's local SFS partition) if that makes sense. There is also the option to install the OS "directly" to a disk or thumb drive and not use the SFS method, but I kinda like the separation and encapsulation of different sessions.
As for difficulties, certain versions don't work on particular computers - maybe they don't have the right drivers or settings out of the box. I don't have the knowledge or a lot of time to mess with such low level details, but if you know Linux or are good with that kind of thing you can probably troubleshoot. I just deal with it by having a bunch of different versions on bootable thumb drives, and I just try throwing them all at a given PC to see what "sticks". I've been able to get some version of Puppy to work on just about every computer EXCEPT my Microsoft Surface Pro 3, which runs Win 10 Pro and uses bitlocker for its system drive. I tried turning off secure boot and a bunch of other BIOS options, but could never get any version of Puppy Linux (or any other portable OS) to boot on it from a thumb drive. Oh well.
I mainly use Puppy to do utilitarian stuff like repartition drives and just play around with Linux. To be honest, I am not crazy about the interface for any Linux I've tried. I have tried different desktops, but compared to Windows, the behavior and "feel" of the GUI - stuff like clicking / grabbing / resizing Windows, selecting files, etc., is just hard. It's much easier to control the mouse and grab things with it in Windows. That and the lack of all the familiar Windows keyboard shortcuts in the file explorer, really makes it less comfortable for me. I bet that stuff can be tweaked, and I have tried over the years, but haven't found settings that really replicate the feel and ease of a Windows desktop (any version from Windows 9x upto 10).
I have also tried Ubuntu, Mint, Zorin OS, and others. Zorin was supposed to be as close to Windows as Linux gets, but it wasn't even close, and I spent hours and hours just trying to tweak it to replicate the Windows Start Menu / search bar behavior with no luck. That was a few years back, maybe they've improved it, but I don't have a lot of time to mess with that stuff (and besides I much prefer the portable/small OS format like Puppy over a permanent install).
Anyway that's been some of my experience with Puppy and Linux in general. I'd be interested in trying QB64 with Puppy, which would definitely make Linux more useful to me...
Hope this helps.