So yeah, I have a desktop and a laptop. Both are running Windows 8.1 Pro. The laptop has a multi-touch screen and since my desktop stays offline I would like to be able to do it via ethernet crossover cable. I want to be able to switch back and forth between the two machines, so that I would be able to use the touchscreen on the laptop. I would also be able to rotate between where the two displays are located, if one is on the laptop screen I want to be able to use the monitor for the other. Any ideas?

 

teamviewer comes to mind...

 

First off, you can't use a laptop display as a monitor for another computer without some noticeable latency (even if it's on a high speed LAN) especially regarding the sound coming out of that computer and you want the sound streamed to the laptop's speakers.
It's because of the limits of this VNC like technologies and having a 1Gb port does not make a difference unfortunately.

But I think you should try and see if it works for you. you should also be aware of higher CPU usage on the remote host (in this case, the Desktop PC) because it constantly sends what happens on screen and receives user inputs.
Team Viewer is not a good option. it's optimized for connecting to a enterprise workstations/server on a remote location.

Now my suggestion would be:
1) Use AnyDesk or NoMachine. Or something with a similar technology cuz these won't send images but the changes and are heavily optimized for LAN connection. there was a program called AVStreamer. it had a bright future but I guess the dev moved on since 2014.

2) If you have a spare iPad, go grab "Duet Display" app. it's made by former Apple engineers and it's lightning fast and supports multi touch.
There's an alternative for android but it's not as fast and stable as the iPad app.
https://play.google.com/store/apps/details?id=superle.airduetscreen