Compatibility of Windows 7 Homegroup and Windows Vista Domain

In computer networking, a workgroup is a collection of computers on a local area network (LAN) that share common resources and responsibilities. Workgroups provide easy sharing of files, printers and other network resources. Being a peer-to-peer (P2P) network design, each workgroup computer may both share and access resources if configured to do so.

Perhaps a little bit of Microsoft Windows history would help building the context,

Windows for Workgroups is an extension that allowed users to share their resources and to request those of others without a centralized authentication server. It used the SMB protocol over NetBIOS.

so,

The Microsoft Windows family of operating systems supports assigning of computers to named workgroups. Macintosh networks offer a similiar capability through the use of AppleTalk zones. The Open Source software package Samba allows Unix and Linux systems to join existing Windows workgroups.

Workgroups are designed for small LANs in homes, schools, and small businesses.
A Windows Workgroup, for example, functions best with 15 or fewer computers.
As the number of computers in a workgroup grows, workgroup LANs eventually become too difficult to administer and should be replaced with alternative solutions like domains or other client/server approaches.

You should be able to share out a printer on your home LAN, and have it accessible by any computer on that network. If both are running Windows XP or later, no special software (other than perhaps drivers) should be required.

The only limitations would be those that may be imposed by group policy (preventing you from installing things to the work laptop) or by your VPN service (preventing you from accessing resources on the LAN while connected to the VPN).