So, I've been chewing on this problem for a while now, but have finally become too frustrated with failed searching and attempts to fix it.

The problem is this: I have 5-6 computers on my home network, two wireless routers and multiple printers. Most of the computers are simple Windows-based clients on a shared workgroup, a couple of them are linux-based (various flavours of debian/ubuntu and fedora), and one of them (the problem pc) is a Windows-based domain machine that frequently is connected to a corporate VPN. I want to be able to seamlessly print from any of the given machines on one of the printers. Both printers are USB-based (one is a Samsung ML-2010, the other some simple HP multifunction).

The printers are currently hooked up to a stationary "office" computer, which receives minimal use, running Windows XP (on a P4, with under a gig of RAM). This is currently the only hard-wired machine on the network, everything else is wireless. I run two routers, because one serves the wifi-N machines and the other serves the wifi-G only machines. They are hooked up so the wireless-g router (on DD-WRT) is a DHCP "dummy" (it forwards the DNS addressing to the wifi-n router, not running DD-WRT).

All the workgroup computers print flawlessly off the XP workstation. I've even managed to get the linux machines printing through it. My issue is the one domain/VPN machine (on Windows 7 Enterprise (with lots of image modifications thanks to the company's IT dept.)), which I can't connect to the workgroup and can't think of a better way to connect it to the printer.

I realize that purchasing a usb print-server box would be easiest, but I have extra machines around that I would be willing to set up to configure it otherwise. I was hoping I could do something that would set the printer to a local IP address, which could then be accessed by any machine on the network. Is this possible, and if it is, are there any suggestions on how to set it up (like, router OSes, configuration settings, etc.)?
Or is there another easier solution that doesn't involve purchasing new hardware?

I would double-check the sharing permissions of your printer (on the XP workstation ofc) and set them in a way that shares the printer in r/w mode.
IDK if I am wrong or if I said too crazy things, it's 1:30am over here.

The issue is that the Win7 Domain laptop is unable to find or access the XP workstation on the network. It can connect directly to the wireless router's admin page, but it can't find the actual XP machine, even when trying to connect via the computer's local IP address, assigned by the router.

is the dummy router doing NAT?? now you can't set DD-WRT to be a WIFI AP only?

After posting this, I decided to just find a linux server distro and just trial-and-error it out. I picked Zentyal, because it didn't seem too daunting. It took a few hours to install and configure, but I managed to set it as my internet gateway and network DHCP host by connecting the cable modem to the server on eth1, and connecting the one router on eth0 with a static IP that was in the same address block as my two routers (192.168.0.x). Then by turning off the DHCP servers on the two routers, I was able to chain them together and hook one of them to the server, so all the machines are on the same DHCP server. Then it took me the better part of 45 minutes to figure out CUPS and how I could connect all my machines to the printer.

Now it's done though. Months of trying to figure it out just took an evening of fiddling with it.
Although I still haven't figured out how to access the admin page remotely from my other machine. But I'll leave that for another day.