I am running Mint 19 xfce 32-bit on a Pentium 4 with 1gb of RAM. Works okay. Not seeing showed records, but useable for, like, 2 or 3 tabs or for word processing. You could probably do a bit better with that system.

I have a device with 2gb of ram with mx linux, and it works fine. Here's a few tips for any distro when using such configuration:

1 - if possible, enable multilib and run 32-bit versions from your heavier software, like the browser (the entire system as 32 bit helps a lot, but most distros seem do be dropping it)
2 - use zram
3 - in the browser, look for some form of tab suspender addon
4 - try alternative lightweight software for your stuff (for example, abiword instead of libreoffice)
5 - block ads in your network, to prevent the device to even process them
6 - don't use the browser to wathc videos. Look for native players. In fact, avoid doing anything in the browser and look for native software when possible

I find it quite fun to use a constrained device like that, and it helped me change a few habits I considered to be bad for me, as well as it helped me focus more on my important stuff

USB should work fine assuming the system itself can boot to usb (googling it looks like it can, you may have t hit delete to enter the bios to tell it to boot to usb first though)... distro inherently isn't a huge varient in terms of resources used however desktop environment is. You absolutely want something with a very light desktop manager, LXDE, XFCE etc... So depends, if you are looking for something very simple... I'd say probably Linux Mint XFCE edition, if your goal is to learn how linux works, don't mind reading up some documentation, arch linux is amazing.

If you have experience with any distribution or like something, almost every distro has a version that's distributed with a light weight desktop manager. The desktop manager is where the bulk of the system requirement weight is.

Damn, a dv6000 series, I had a dv6175 twenty years ago....

What are your plans for it, you mention saving it from ewaste due to it's many ports, so I suspect you will use it for diagnostics or labwork.

If so, you would probably be best suited with an older version of Ubuntu, possibly something like 8.04 or so.

That should run decent on the machine and allow you to use the ports for whatever labwork/testing you may require.

But be careful and avoid browsing the public internet with it.

That's a really old system, here's my recommendations in order:

1. Linux Lite
2. Lubuntu
3. Q4OS

All of these have minimum system requirements that are lower than your system, so they should install and run fine. USB should be fine to boot and install any one of these.

I wasn't sure what to recommend so I found this.

https://distro.watch/distros/category/ram-2gb