ORD isn't too bad; MDW is easier but it's a pain taking both trains--plan on 2 hours.
MEM is a pain in the summer--especially when they put -9's on the route and are weight restricted--but atleast they aren't hauling mail anymore. When there are 4 banks to MEM it's not too bad, only three and it can be tight. MCO-MEM you need to be on the 6am flight. A good backup for me was Airtran to ATL first thing in the morning when their loads were light then I had NW, DL, and Air Tran to get me ATL to MEM.
(a few years ago) DL usually runs one of each kind of widebody between MCO-ATL for line checks and OE (lot easier than going to Tokyo, right?)--so there were 763, 764, 777, M11--all kinds of fun stuff to sit up front it....but I haven't been on them in four years, so I don't know what's coming to town.
The MCO employee parking lot is freaking huge--it takes a while to get from your car to the gate--so plan accordingly.