You can mail order caps from
www.radiodaze.com or from Just radios (I can't remember if his address is justradios.com? should be a link around here, or on antiqueradios.com) Radio Daze offers quick service; Just Radios carries a wide range of values. Both have competitive pricing.
For the 160mfd caps, I use a 100mfd in parallel with a 68mfd. I haven't found any new 160mfd caps. I've recapped a similiar Zenith and it wasn't too bad; you may have to be a little creative with where you mount the new caps so that you have enough room under the chassis. If you don't have any terminal strips see if you can order some of those when you get the caps. These make it a lot easier than just having things "up in the air". I have another similiar Zenith that is ready to recap and I thought about doing it now and posting the photos for you, but I'm not sure if I'm good enough to set any kind of example!