Staying in Zurich, Wilderswil, and Bern
1) Just wondering if there is a way to transfer my luggage between each of these cities when I move?">>
You'll probably need a train ticket or rail pass to use that service.. Might need to use Interlaken Ost, instead of Wilderswil for one luggage destination...I did not check the station lists on the link above. Wilderswil is not a large station.; I.O. is close by, and much larger.
While you are there, take a look at the trains up to Schynige Platte.