Leafpad is by default along with Abiword.Geany can be installed via Yumex along with the Libre-Office suite +pdf viewers.There's a lot of choice of Software one can install.
Installing from USB you can use Unetbootin:
(Available in Windows & most GNU/Linux Package Managers )
Quote:
UNetbootin allows you to create bootable Live USB drives for a variety of
Linux distributions from Windows or Linux, without requiring you to burn a CD.
You can either let it download one of the many distributions supported
out-of-the-box for you, or supply your own Linux .iso file if you've already
downloaded one or your preferred distribution isn't on the list.
http://unetbootin.sourceforge.net/
Concerning which other Distro would run best on old machines.Most GNU/Linux Libre distributions do that very well the easiest to install are:gNewSense & Trisquel Debian based,Dynebolic & Musix are more specialized
in Music & Video.Parabola,Dragora are more complicated to install(Disk partitionning).
Check out the minimal requirements as exemple i have 1000MB of RAM on the Dell Latitude |D610 32bit.
Quote:
gNewSense 3.1 with GNOME desktop for i386
Minimum system requirements:
Processor: 1GHz
Memory: 512MB
Hard drive: 5GB