Hi Ron,
I think it is just a timing/traffic saturation issue as far as ATC flight following goes. Two years ago we flight followed right into Kissimmee coming from the Northwest, but most years around S&F time they do drop you. The arrival into Sun and Fun is fairly easy however the volume of traffic keeps your head on a swivel until you get interval on the arrival.
Download the Tampa-Orlando TAC 44 from here:
http://aeronav.faa.gov/index.asp?xml.../chartlist_tac
This will give you both the Orlando and Tampa TACs and a VFR Fly 44 chart for Orlando which will show you the VFR corridors around the Orlando Class B that you referenced. Once you depart KISM it's clear sailing into the arrival for S&F. Have a good trip!
Rocky