I'm pretty careful when it comes to security. I asked my IT instructor (who is the most paranoid person ever when it comes to security) about a program called LOG ME IN found at
http://www.logmein.com . I saw this program and liked it but had my concerns about the security of remote access. He said it looks legitimate to him. I tried it and think it's the best thing since sliced bread. there is a free version that allows full remote access but does not allow file transfer. There are other paid versions of log me in that support that. The free version allows access to all features of the paid version but only for a limited time.
This program needs to be installed on the computer you want to access only. Then that computer can be accessed from anywhere with an internet connection. Its very easy to install so you can guide her through it.