Joining Remote Clients to Domain

[owensdj]

I connected an office network to another over a VPN. The main office has a AD domain but the 2nd office has 2 XP Pro computers in a workgroup. The remote computers will be running the Terminal Service client and connecting to a Windows 2000 Terminal Server at the main office. Would it be a good idea to have the 2 remote XP Pro computers join the domain, or should they stay in a workgroup? Also, would the 2 remote computers be able to contact the DHCP server service on a Windows 2000 Server at the main office over that VPN?