You don't need the full protector kit really, just the munchkin play field. More protectors won't really hurt I guess, except I hear the rollover protectors make them not activate sometimes.
Munchkin protector is actually really easy to install. First remove the playfield as instructed in the manual, lay the protector where it goes, mark the spots to drill with a pencil, get out the appropriate drill bit and make sure to mark off the depth you will be drilling to on the bit using tape. That part is very important, you'll be kicking yourself if you drill through the playfield on accident. All in all I'd say it took me about 15 minutes to put on. Although I did have some experience with removing that mini playfield before, but I don't think it would take longer than a half hour.
The thing that got fiddly on that install for me was - I didn't want to cut the cable ties, but you need more reach than the data cable will give you. I ended up carefully sliding the wires around within two of the ties, feeding the data cable through those two ties to get extra reach, and then doing the reverse to get the data cable back into the ties after installing the protector.
Also, my pops came with mylar in there from factory. I'm not sure how common that is, but mine definitely has mylar there and it wasn't me.