If AAF is built out to Tampa - very big if at this point, it will exit the airport near the south exit, and then follow SR417 ROW to I-4 Median. It is going to be a much more expensive project overall than the Cocoa - OIA link, and will not be constructed unless there is money forthcoming from the state, the feds or both.
Should AAF ever build in the Interstate 4 ROW, the route would pass directly through Walt Disney World property, so for those dreaming of a possible Disney station, that would be the (slim) possibility. Again, as Jis noted, that's a really big if. Frankly, despite assurances financing will not derail the project, I'm not completely convinced AAF will ever reach Orlando, let alone further expansion. In their defense, I didn't think they'd get as far as they have already either, so we'll see.
Oh either they will reach Orlando or they will shut down entirely. Long term, they don't really have a business case without reaching Orlando, unless they are able to capture an extremely unexpectedly high proportion of traffic between Miami and WPB. Heck, anything is possible I guess. The beauty of their approach is that the real estate developments around the train stations will not necessarily crash and burn if the trains cannot be run profitably. The net profitability will be significantly lower due to horrendous traffic etc.
There really is no particular reason that they won't reach Orlando. The rearranging of the bond into tranches is ll about increasing the ease of getting there and making the construction through Martin and Indian River Counties entirely independent of any bond issuance. They are using bond money to finance the West Palm beach segment instead post facto, and transferring internal money to construct through those two counties. They should not have any difficulty with county specific bond issuance for Brevard or Orange counties.
If they build to Tampa, they won't be on I-4 median north of the SR417 intersection, so they will be far from Walt Disney World Property, which is mostly to the north of there.
There is very little that stops them from reverting the whole thing to a Miami - JAX service, in the remote case that Orlando fails to materialize. That expansion is relatively cheap, possibly cheaper than the Cocoa - Orlando segment if they already have the segment upto Cocoa even halfway in place. It does not require double tracking all the way, just a bunch of judiciously placed crossing sidings and a few stations on their own property with associated real estate development to fund most of it.
I agree about the rearranging of the PAB tranches in order to avoid funding the Treasure Coast. However, I don't think they will build the Jacksonville to Cocoa (or Miami if Orlando isn't built) section anytime soon as the traffic is not there to support the 300 miles of upgraded track. However, the Tampa expansion seems more doable based on potential traffic between SE Florida and Tampa as well as the heavy local traffic between Tampa and Orlando. Even at 3 lanes each direction, I-4 is packed almost 7 days a week no matter the time of day. I have copied the trip numbers between each region of Florida below from the 2006 Florida Rail Vision plan. Although a bit dated, it shows that trips between Tampa and SE Florida alone are half of Orlando to SE Florida. Additional trips between Tampa and Orlando are very high and would add to the total traffic on any Tampa expansion. Trips to/from Jacksonville/NE Florida are not that significant in comparison.
I haven't heard anything before now about AAF using 417 to get to I-4. Is that what AAF unofficially has told you? I had always assumed they would follow 428 to the convention center area (along the old proposed HSR route) and try to pick up a stop around Universal or WDW versus 417 which skips those areas as you state.
http://www.fdot.gov/rail/Publications/Plans/06VisionPlan/ExecReportFinal.pdf
Florida Intercity Travel in Selected Markets
Market Total Person Trips (2000) Total Person Trips (2020) Total Person Trips (2040)
S.E. Florida - Central Florida 9,446,524 18,420,722 30,394,191
S.E. Florida - Tampa Bay 4,850,862 8,537,517 14,086,903
S.E. Florida-N.E. Florida 1,304,613 2,283,073 3,767,070
Central Florida-Tampa Bay 14,156,497 29,162,384 48,117,933
Central Florida-N.E. Florida 3,537,194 7,321,992 12,081,286
Tampa Bay-N.E. Florida 1,545,914 2,906,318 4,795,425