To address the cab issue.....
We find Disney transportation to be good - as long as you are going "the well traveled path" Resort to resort transportation can be a bear. So can leaving or going to the park when the path is too well traveled. Offsite resort shuttles I've never done, I'm given to understand the quality varies alot depending on which hotel you are at.
For these occations, we use a taxi. Its about $15 a trip BW to MK, about $50 from MCO to BW. As was mentioned, a taxi can be caught where bell services for your resort is. If your party won't fit in a standard cab, a minivan that will fit about seven people can be called - and won't cost you any more money. At the parks, there is a cab stand somewhere near the bus loading area - except MK where its out by the TTC.