Frankly though, the primary clientele that AAF is looking for is not going to be the transit bus riding type. They will do SunRail and Maglev riding type, and mostly they will rent cars or get onto Disney Magic Kingdom or other shuttle buses at the airport, or pick up cars left at the various airport related parking facilities. AAF ridership projections do not depend that much on general transit access at the Orlando end. Any that materializes will just be gravy.
Maybe initially that's a good strategy.
But by and large, the world is divided into those who like to drive and those who don't. Those who like to drive will not be seen in a train unless pressed very hard. In other words, hardly ever. Pursuing this demographic and trying to convert them is mostly a pointless exercise Then there are those who like trains and want to use them. Some of these may be the typical captive bus clientele, often being from the underpriveledged demographic. But there is increasingly also a different demographic of people who like transit. They are middle-class folks, often of the younger generation, who never bought into the car = status symbol thing. They can afford to drive but choose not to if they can avoid it. Their numbers are increasing all the time, as reflected in increased interest in downtown apartments and the often criticized gentrification of formerly undesirable neighborhoods .But because they are car free by choice, their being car free depends on workable alternatives being offered. Build a decent transit system, build an intercity rail system, and the car free will come flocking to use it. But cut them off by building car-centric out of town peripheral stations not connected to the areas where they live, and they won't be able or willing to use it.
I think a lot depends on the area you're talking about and how bad the traffic is. For example, if VA had gone with an option to build a bridge across the James River to link NPN and NFK (this was an option considered early on in the Hampton Roads HSR planning process) and made the whole operation double track, I think you have plenty of folks who would have used a high-frequency DMU service to shuttle between sides of the water even if they had to stick cars on each side, such is the atrocious traffic on the HRBT. [1]
In the case of Texas, as long as you have a Suburban Station and a Downtown Station on each end you should be able to sweep up a good deal of traffic. You'll have car rental facilities at each end, but knocking a four-hour drive down to a 90-minute train ride is enough that even assuming half an hour of transfer time at each end you're still 90 minutes ahead of where you'd have been...if traffic was cooperative. Throw in bad traffic and I'm fairly sure you can add another hour or two to that on the wrong day. Downtown Dallas is also pretty transit-friendly (and generally getting better as time goes by, too, from what I can tell), and it's "good transit" (i.e. light rail and streetcars, not buses) so I suspect you can get your businessmen to ride it.
Down in Florida you have a tangle of groups AAF would be looking at, but you're right: This is not the "bus crowd" in some sense. Give them high-frequency SunRail to downtown (and for the record, it is quite possible that the airport will happen before Deland does because of paperwork issues...apparently the ridership estimates for Deland are low enough to cause issues qualifying for funding and I think someone screwed up a round of /something/) and you'll get transfers, if only because I have had far too much experience driving in Orlando to call it "pleasant". South Florida is a similar story...if the streetcar projects down there ever actually end up /going/ anywhere useful (like, say, connecting SunRail stations to FEC stations or going more than a few blocks in any direction) then using the trains to get downtown will be a viable thing.
Anyhow, the point is more that you have an increasing number of areas where I think two other groups exist:
-Your "want to drive" folks (generally older);
-Your "don't want to drive" folks (generally younger);
-Your "wouldn't mind driving if driving wasn't miserable" crowd; and
-Your "want to drive but not too long/not after dark" crowd.
Texas Central is shooting for #1 and #3 (by simply killing driving on travel time). AAF has a lot more of #4 to work with (and #4 is basically what #3 turn into as they get older) alongside substantial elements of #3 given that traffic in South Florida has been atrocious for decades (there's a reason that Tri-Rail was able to grow like it did). I think Florida has more of the "don't want to drive" crowd as well, between Northeastern transplants (who know what "taking the train" is) and a long enough legacy of bad traffic (especially in South Florida).
By the way, when I've been down in the Orlando area my experience in listening to the radio is that there isn't much of an anti-rail crowd to be had around Orlando...the main thing I've heard on the talk radio down there is a bunch of complaining that SunRail doesn't run enough service/doesn't go enough places (for example, there was a special set of weekend service to a dining event in Winter Park...but the geniuses at SunRail didn't think to try and arrange an evening frequency, resulting in the last train leaving at like 1600 rather than at 1900 or so as would normally be the case IIRC). You've got a NIMBY crowd in between the two areas (which I predict will more or less collapse once stations start going in) but that's about it.
[1] There are some fascinating "roads not taken" to consider here. A DMU-based service could easily have taken modest upgrades on the Virginia Beach line as-is (class 3/4 track would have sufficed). You'd have simply had The Tide terminate at Harbor Park station and act as a downtown streetcar system. The DMU lines would have gone out to the Oceanfront (I think you would have needed to extend the line by all of four blocks to get to Atlantic Ave) on the one hand and wrapped around to roughly the James River Bridge on the other (which would have hit Suffolk along the way); you could probably have worked something out to run a service to the gates of Norfolk Naval Station as well. There would only have been limited overlap with existing mainline freight service right at Harbor Park Station (as well as on the Peninsula Subdivision, but that could arguably have been mitigated at least somewhat). All I can say is that "At least it would offer a competent connection between Norfolk and Newport News for less than $3bn" (the estimates at the time for the bridge and the tracks on each side were around $600m).