I'd assume you'd be fine with some
portable apps in your SkyDrive, however because most Windows programs tend to touch the registry and store user data in random places, in general no.
As for the iPad, I don't believe iOS allows you to change the install path or do anything.
Edit: Also forgot to mention that yes, if you're on a computer where you can't/don't want to install the SkyDrive application, you can temporarily map it as a network drive.
Just go to Computer>Map a Network Drive and use this "https://d.docs.live.net/(user id here)"* Choose "connect using different credentials" and set the login credentials to your live id and password.
*To find your user id login to SkyDrive an open any folder, it'll be the string after "cid=" in the URL.
