I tried Unreal4AR the other day with my Vive and the built-in camera. From memory, I think Unreal4AR is actually based off of ARtoolkit and so just going with Unreal4AR is probably your best route. I managed to get it working pretty quickly.
You’ve probably already seen it, but the main thread is here:
I think there is a sample project to get you started in there somewhere. There might be a few version though and so check you have the latest.
Between the thread and the docs on the Unreal4AR site I was able to fairly easily get a basic scene set up that could detect a printed target. Took a few hours in total to read up on it and get it working. Did not try with an Android device, though if you are already setup to package for Android and familar with the process then you should be able to do that pretty easily too. If you are not then you can follow the instructions for setting up to deploy to Android on the UE4 docs (https://docs.unrealengine.com/latest/INT/Platforms/Android/GettingStarted/).
If you just want to test on your PC then I think you can probably get up and running more quickly with a webcam attached to your PC. I think some people had trouble with some models of camera, lots of good docs over at artoolkit.org that are relevant for anything you do with Unreal4AR:
Hope this points you in the right direction.