I wouldn't bother testing your VPN connection latency to the SWTOR servers specifically (presuming you have a VPN exit point at roughly the same region as the SWTOR region you're attempting to join). Just fire up your VPN and use any bandwidth/latency test to check out the general latency you'll be getting. You can usually choose a location for your bandwidth test so you can get a range of probable latency by testing at different locations around the country you VPN into (i.e. if your VPN is US East Coast, test latency on a couple points on the East and West coasts).
It might be difficult to tell what latency is acceptable for this specific game, but I think you'll get a rough answer that will either rule the game out or lead you to investigate the actual bandwidth/latency requirements.