Multiple Accounts On Same Win 8 Machine

I have two different Microsoft accounts on my Windows 8 machine, which is a laptop. One of them is an account I got from my ISP and has been in use for years but that one is disappearing in a few days (I think) because I cancelled my account with my ISP. The other account is one I created within the last couple of weeks.

In transitioning to the new account, I'm finding it considerably more work than I expected and wonder if I am ignorant of some easier ways of doing things. For instance, I was surprised that the applications installed under the older account aren't visible under the new accounts. Is there an easy way to make them visible or do I really need to reinstall the same applications under the new account from scratch? For example, let's say I have a game like Taptiles on the old account and want it visible under the new account: do I really need to do a fresh install under the new account? Or is there an easier way to be able to play Taptiles from the copy I originally installed under the original account?

Also, what is the easiest way to pass data back and forth between the two accounts? I did a copy within a file on the original account and switched to the second account to paste that information in and was disappointed to find that it was not possible. I ended up sending an email to myself then copied from the email on the newer account. It struck me that there must be a better way but I'm not sure what that would be.

Also, with respect to XBox, some of the XBox games had accumulated fairly substantial scores as a result of playing the daily challenges. Is there any way to roll the scores from the old account into the new account, even though they have different "gamer tags" (the ID by which I am known when I play TapTiles or Mahjong or whatever)?