No real solution here, just musing in public.
You could carry a small portable router with you, something like the AirPort Express. Or maybe 3G Hotspot like Verizon's MiFi, if you want internet access too. Expensive, that last.
For printing you'd need an AirPrint capable printer, since you won't have a computer to host the drivers.
I don't know of any iPad apps that let you access a printer's scanner. The best I can come up with is a decent 5mp camera (or bigger), the camera connection kit, and one of the apps that lets you turn pictures into PDFs. Some of them even have adjustments that mimic a scanner's abilities. Wouldn't need a network for that.
If there is a wired network available, and the host would let you, you could plug your portable router into that and access whatever stuff they have. Still need to install, with permission, some software on local computers to print. Unless they have an AirPrint compatible printer.
Now, if you want to carry a printer, laptop, and portable wifi router you can do whatever an iPad is capable of; minus the internet, unless you have a local wired network or portable Hotspot to play with too.
All in all, an interesting problem in logistics that just proves that an iPad isn't quite ready to replace a laptop for everything.