I think I am misunderstanding you. Are you saying you want your DD to play 18U travel ball events after she plays a year in college? If so, why?Hmm, 'matter of fact' responses like this are pretty frustrating. Obviously all of our experiences are different but I'm going to have to leave you to do the specific showcase research. That said, Triple Crown, in fact does not allow college players in at least several of their showcases. Pretty sure TC would be considered 'reputable' right?
I understand that college players are not allowed to play in Most sanctioned events, which only makes sense. In the past there have been some TB teams that had a handful of college age eligible to come back and compete in ASA Gold Nationals and I think they won. There were some pissed off people. Might have been a team from the East Coast.
There really should be no reason for a kid that played in a year in college to come back and play Travel Ball even if they are age eligible. My DD played 3 years in 18u and is happy to leave part of her life behind. In the Houston area there are no 23U summer leagues, but some coaches brought together college players that live around the region to play double headers and DD did some Sunday afternoon workouts with a bunch college players.