We did the MK and Epcot parks in the same morning. As a previously posted, pick up time was listed as 5:45, and we went until 9. Actually, we were in Epcot a little later than 9, but we got some great shots! (pics in PJ, link in signture)
and yes- there is a "discount" if you do MK and another park in the same day. I think the price is $1400 for MK + another park, if I remember correctly. I don't have my BEO with me, so I can't be sure.
I was quoted epcot/ak/dhs photosession at $650 each. and MK alone is $1000 ( I think).
I don't think they give you a discount though if ,say you decided to do 2 non magic kingdom parks. I'm sure someone else will come along and correct me if I'm wrong though.
We actually only scheduled the Epcot at first, and later added the MK and were given the 1400 price instead of being charged seperately for them.
Purchase Lurkyloo's book, all the pricing is in there!