You can fly the 377 into TNCM, take a tour in the P-51, try landing at the short strips in the P-40, and...uh...overheat and practice ditching in the Spit.
Personally, I think Spitfire has by far the superior STOL capabilities when compared to P-40. Landing at St.Barts, even from the downhill side (which in reality is the only permitted one due to no possibility for go-around from the other direction) is, while not perfectly routine, quite possible. And also (almost) safe as long as you have some degree of common sense
and prepared to swallow your pride in front of spectators and abort the attempt if it proves futile. Sure, there's some torque twist if you have to abort it while flying at stall speed with flaps down, and that's pretty much how you much approach St.Barts because if you approach with normal speeds, you're not going to get into speed for a 3-pointer at the first half of the runway. However, with some experience, landing Spitfire on St.Barts is very possible, even to downhill, thanks to high drag flaps.
P-40 is possible from the wrong direction while Spitfire is from both. P-51D I've yet to try to land there. Nor have I tried P-40 after the latest few Core versions so it's short field landing capabilities might have improved since then.
As for Saba, you can take off from it with a B-17 (using the drop from the cliff to gain more speed). However, you cannot land it there so it's obvious there could be no B-17s at Saba unless they are shipped in pieces and assembled there...
B-377 I probably haven't tried to either take off or land from Saba or St.Barts. I don't expect it to fare any better than B-17 if even that well.