We all know that the Surface has limited storage. I was messing around and found a quick change to a registry key that lets you change where windows store apps are stored when installed. Tested and working on my Surface 32gb. see below for the key:
change the key labeled PackageRoot to whatever directory you want, and all new apps will install in that directory.
Note: this does require that you change owner and permissions on the Appx registry folder so that you can edit the key. I have tested this will no ill effects.
You can also change the app repository to another directory by changing the PackageRepository key.
Test on a class 10 32gb card. Hope this helps!