I've been working with Indesign & Illustrator CS6 for over 10 years on a MacBook but am thinking of upgrading to Creative Cloud on a Windows PC. What I'd like to know is, is it possible to open / alter MacBook created CS6 files on a new Windows PC or Windows based laptop?
INDD files are completely crossplatform. The only issues would be Mac-only fonts (regardless of platform, you should be using OpenType only, anyway) which will not work and if you try to open files created in a later version.
If you're moving to Creative Cloud the second should be no problem at all.