DEW ET! I don't think you would have much trouble. The Buffalo module is a snap, its only two leds and four standoffs, it doesn't get any easier. The power supply modules are also super easy to follow and as long as you work your way up populating the board by the height of each component, should also not be very intimidating. Their are two little SMD choke/inductors on each of those, but they are super easy if you just tin them and the pads and then heat the pads while you hold them down in place with tweezers (easier then it sounds even). The only challenge you might have would be the IVY which has much more components to populate the module with, but I would suggest you try it. If your too scared, you could also spend the money you would have spent on someone else doing it for you on a pre-assembled Zapfilter from parts connexion and not buy the second transformer, LCBPS, or IVY for a little over $100 more then you would have spent on those.
Overall, I think you can do it, the casework is going to be by far the hardest task there. Get yourself some nice pre-drilled front and back panels from Front Panel Express with the money you save if you don't want to drill yourself. Just brush up on the tangent tutorials.