Test driving an SX-P? Forget it. Most if not all at a dealership will be pre-sold, and most dealerships won't let someone test drive a pre-sold vehicle. You can test drive another trim level, and then order an SX-P if you wish.
You might get to look at an SX-P - I was able to at least look at one by chance before I ordered. Southwest Kia of Austin might have one on the showroom floor - simply because they have a massive markup on it - but I seriously doubt they'll let you test drive it.
In the Dealer Inventory section, Donovan at Huffines Corinth and Stephen Cantrelle at Classic Kia of Carrolton have had SX-Ps recently available.
If you want it by this summer, I'd order now from a high volume dealer such as those above. There's no risk to you. Order it, when it comes in, take it for a test drive and then decide. If you don't want it, someone else will. Stephen posted about an available SX-P yesterday (presumably someone backed out of the order) - and it sold in 30 minutes.
Can also call Moritz Kia up near Dallas - they get quite a few prestige trims.
See this post and discussion too (see a few posts above this one in the thread to learn how to filter production spreadsheet on forum).
Is there a way to do this for the SX model in Gravity Grey or Everlasting Silver? Yes, of course. But you might want to be more specific. Towing package / no towing / don't care? Prestige / non-prestige / don't care? AWD / FWD / don't care? Interior color - or don't care? You can do it here...
tellurideforum.org
In San Antonio, it shows that Ancira Kia was allocated two Black Copper Dune Brown SXPs vehicles on 12/17 - they might be in transit still. They are most certainly sold. World Car Kia dealerships (multiple) also had a few allocated to them in December. Probably already been delivered to customers... but there's a chance that they are in transit.