Pc Anywhere / Hamatchi -Problem

I'm being tasked with setting up a worker's home computer to access her works PC from home.
However, an issue remains unsolved.

First the setup;
- The company has around 8 computers behind a 3com NAT router.
- Pc Anywhere and Hamatchi (FREE) are to be used. Hamatchi to be the VPN so the user wont need to fiddle with port openings and the like.
- Windows XP Pro is used on both computers.

Problems:
- I need a solution to allow the user to switch between her two Windows XP user accounts on the work PC (from her home location). She has two accounts and obviously will need to switch between those whilst she's at home to access various files.
- I'm right to believe that with Hamatchi that I wont have to port forward etc etc and just need to enter the Hamatchi IP into PC Anywhere and all should be fine?