Unfortunately the remaster tool it includes, which is meant to allow for custom Live CDs to be created with chosen software pre-installed, seems to be buggy, and continually failed when I tried using it, so this is the alternative way I found to remaster TCL.
Create a basic virtual machine and boot with the TCL Live CD. I used the CorePlus-current.iso, which has some extra software on there, but is still sub 100MB.
Once it's booted to the desktop select TC Install.
Click through the next two screens (formatting options and boot options)
On the install type I checked the Installer Application option as I might need it in my intended application later, but it's optional.
Click through to the next screen where you're selected options will be repeated back to you, and select Proceed.
When it's done installing, shutdown the VM, remove the Live CD image and restart, so that it boots from the HD.
Go to apps, and install the software that you require. In my case I installed Open JDK and Filezilla. (Filezilla also requires libiconv to be installed)
Reboot using the TC Exit options (from the menu go to Logout). The backup options there will essentially create a blank mydata.tgz file structure for you to use later.
Step 3 (Optional)
On the host system, edit the mydata.tgz that you copied over, and add in any necessary files that you want on the Live CD. Thanks to the reboot that you did in step 2, mydata.tgz will have a basic file structure in place, that maps to the home and opt directories of the live CD. Also it puts in a couple of SH scripts, bootlocal.sh and shutdown.sh - these handle things that you want to execute on boot and shutdown respectively, edit those if you need to.
Use an ISO editor (I used ISO Master).
Open the LiveCD, and navigate to it's 'cde' directory
Copy your mydata.tgz to the ISO, and replace its onboot.lst, and 'optional' directory with your own.
Navigate back to the ISOs /boot/isolinux directory and edit the isolinux.cfg file.
Find the line
This line causes it to sit on the bootloader screen for 60 seconds, unless the user selects and option.
I want my live CD to boot without user interaction, and that delay is redundant, so I edited it to
which allows a 1 second delay before continuing to boot the default option.
Save the edited ISO. To test, setup a blank VM like you did in step 1, and select the edited ISO as the boot medium. TCL should load, with your apps and files already there.