Hi Rob!
Great to hear you are starting in on ODK2.
One thing I am going to suggest you start with is some of the initial setup guides as slides we did here:
There are a number of steps, including the ones around installing nodejs and grunt, as well as checking the version, that may help you with your initial problem getting grunt to open a chrome browser (particularly in the 02_ slides).
I think the location/path for ODK2 is pretty flexible – we have stuck the app designer all sorts of places.
We also have definitely renamed the app designer (often with the date of the version or the survey).
You can install either Android studio and then add on SDK packages or SDK directly, directions are in here:
https://docs.opendatakit.org/odk2/app-designer-prereqs/?highlight=sdk#android-sdk
I think you will still need adb, since that is how, say, you get the application on to a tablet.
Hope that helps you progress!
Best,
Caroline