You're looking for a portable version of FANUC Ladder III software for download. Here are some useful resources:
is a Microsoft feature (discontinued but still usable) that allows you to install a full version of Windows on a high-speed USB 3.0 SSD (not a cheap flash drive). fanuc ladderiii download portable
If you're interested in writing a blog post about Fanuc Ladder III or CNC machine programming, here are some potential ideas: You're looking for a portable version of FANUC
The software provides a comprehensive Windows-based environment for managing PMC ladder logic. LADDER-III Programming Software - FANUC America Fanuc Ladder III Portable — What it is
FANUC does not officially release a portable version. Their distribution model relies on standard Windows installers.