RE: VPN vs Terminal server access
Deanne, I access the vast majority of my client's GP via VPN and either Terminal Services or Citrix. The experience is almost as good as sitting in their office. A lot depends on your architecture, internet pipe size, etc. Google 'dynamics gp server requirements' and you should get a link to 'System Requirements for Microsoft Dynamics GP 2013' that you can download for reference.
I also have a document that my company uses as a guideline for GP installs that goes above and beyond the minimum requirements outlined by Microsoft that I could email you if you'd like.