yes - they "search" all bags (and fanny packs, purses, etc.) before entrance at all of the resorts ---they have an area set up before the turnstiles where you line -up. It might slow you down by a few minutes if you are going at park opening or other busy period ---but not by much --they are pretty efficient at getting people thru there. Most people have their bags ready to be searched (unzipped) when they get to the Security person.
Its a quickie search- sometimes I have been asked to unzip my camera bag to prove that was indeed a camera (which was in my backpack), sometimes not. If you are in a hurry (want to get a stroller for example) - you can always send in one person without bags (there is a bypass to the Security check for people without any bags) and have someone else take all the bags thru security and then meet up on the other side of the turnstiles (or at the stroller rental place, for example).
As far as parking at the resorts--- if you are not staying at a particular resort, then you can get a temp. parking permit for up to 3 hours (if you are having dinner there for example).