I got the kit for less than $20 and tried it.
200 GB C drive and 800 GB D: Partition

I emptied the Doc, Picture, Download folders.
I was then able to clone The whole 1 TB drive to a 240 GB SSD.

Afterward I found C: to be 48 GB with 40GB of data. Yes, my desktop was able to boot the USB SSD.

Used Gparted to remove the D: partition.

Clone what was left to a 256 GB SSD.

Copied back everything to the correct folders.

Old C: drive was added to Bottom of the stack

1. is the 256 SSD
2. 2 TB hdd
3. the 1 TB that was the old C and D hdd.

Found this video this morning showing how to do it.