Clients in different domains

I have situation like this:

Company with one head office and one remote office. In the two offices I have two domains with two PDCs. The two networks are connected with eachother through leased line and the routers are configured properly. The SQL Server is on the PDC in head office and "local" clients connect fine. I cannot connect from the remote office. I think that I have folowing solutions:

1. make trust relationships between two domains - it will be hard a little bit because second PDC is samba on linux

2. make all clients in remote office to be members of the head office domain - potential problems if the leased line drops

3. make all clients to log in with same account as SQL Server logs locally - stupid

4. something else - what?

Thanks in advance!
DanielSql authentication is designed for such cases as this.

http://msdn.microsoft.com/library/en-us/architec/8_ar_cs_79kj.asp|||I am with SQL Server authentication and despite of this I cannot connect from some computers...|||Take a look at the following kb and make sure the firewall is setup correctly.
http://support.microsoft.com/default.aspx?scid=kb;en-us;287932