1. Yes. Most file sharing ports will be blocked by the ISPs since they are an avenue for abuse. IF they were open, you would need to forward ports 137,138,139, & 445. However, this would mean that ANYONE would be able to access the shares since most are configured to allow guest access at even a read only level. IN ESSENCE, WHAT YOU ARE TRYING TO DO IS NOT SECURE AND SHOULD NOT BE DONE!
2. see my answer for #1.
3. Most likely, empty connection log means it is being actively blocked by the ISP as it should. Also, most routers are set to NOT allow NETBeui traffic from internal to external anyways. (Even if Microsoft-DS port is specifically for NetBeui-over-tcp/ip)
4. The proper way to network 2 machines in 2 remote physical locations is by using a VPN tunnel. IF the routers support it, create a site-to-site VPN tunnel. This will allow the encrypted transfer of information between the two logical subnets. Essentially, the machines will act as if they were connected to the same physical network. If you cannot establish a VPN connection, you could always use a service like Dropbox (http://www.dropbox.com) which would allow you to share and synchronize files on remote machines while also allowing the redundancy by backing up the info to the cloud.
Please let me know if you have any other questions or comments.
IT Desktop & Network Consultant - MOS Master Certified, MCP, MCITP - Windows 7, CCNA Certificate Pending, A+, Network +