Make sure all users are NOT checking Compact when STC--in Revit Server, this will save the entire file, not just edited workset data / changes to the file.
The internet speed is very slow, and latency is probably waht's causing the 1 hr save time--which is unacceptable.
20 down/up is a good minimum; faster is better.
How large is the Revit file (s) including Linked models? i.e. total in MB.
Try going to www.speedtest.net and perform a connection test. Ping should be under 100ms for decent performance.
Test this on both ends, i.e. each office.
Make sure there are not any "bandwidth hogs" i.e. users streaming video/music, "stuck emails" with large attachments,
or any other such event such as large FTP up or downloads, etc.
cheers