App to use iPad as a second screen? The catch: not using Wi-Fi (wired solution?)

at home I have 2 screens set up in my workspace: my laptop and a larger external. when traveling i would LOVE to be able to bring my iPad and a latop with me and replicate the exact same workspace on a smaller scale, and not be beholden to being required to have the iPad and the MBP on the same network (or any network at all, preferably, to save $). don't want to use a wireless hotspot for that reason, too.

so is there a "wired" solution to this desire? anyone know of anything like this? seems impossible but i figured if anybody would know it's likely you people.

aaaahhhhh so an airport express as an internal network, yes, that should do nicely. for some reason i always attribute a wifi signal to needing an internet provider attached to it, but it doesn't necessarily need that, correct?

Hmm. How's at now?