When I went to Six Flags I was about 14 DPO and already the blood pressure changes were starting. I asked the doc if the spotting could have been implantation and he said no. It was likely form weakening on the blood vessels as they relax and likely brought on by the rides, though bleeding in early pregnancy is not uncommon.
I think since you've read the stuff on FF, you know that 14 DPO is perfect implantation time. I would be 10 bucks that if you had NOT mentioned going to 6 Flags, he would have said that was implantation, LOL.
By the way, it's nice to hear from someone who had extremely early signs. My boy got his start on our wedding night, we had 6 days between that and our cruise. By then I was up a cup size and more mellow than I have EVER been. My entire mood was like I had been taken over by aliens and given happy pills, LOL. By the time we got well on our way on the cruise, my sense of smell was intense (had not even thought that they allowed smoking in the cabins, but they do, and that was misery for me!). Blue veins started popping up on my chest by halfway through the cruise, and I could have 2 Mango Tango rum drinks (total, over 2 days, not "at a time"!) before my body cried NO on that. By the end of the 7 day cruise (14 days past wedding night) I was up TWO cup sizes.
I actually didn't need a pg test, but hubby was tired of me going back and forth and brought one home, so I used it. But the signs and symptoms were big enough that I never actually needed one, and my husband was actually MORE sure than I felt, so his reaction to the positive pg test was definitely NOT one to write home about, since it was confirming what he 100% knew anyway.
Star Tours shakes you around a bit, that's likely why it's on the list.
Splash they are likely just CYA.
Actually all of it is just CYA on their parts...there are often posts on threads like this by people who talk about it with their mothers, and their mothers went on Matterhorn well into pregnancy and nothing bad happened, etc.
But like I said, I went on Indy (and possibly Space) on our '05 trip several days "late", and the next day it started, so the link between the two upset me and I won't do that anymore.
I am so sorry for you and for DH!!! (((((Heartfelt Hugs!))))) It took my DH and I 18 consecutive months of TTC before we heard the good news. *Please* do not lose hope... and PLEASE go stand at the Walter Disney 'partners' statue when you are there... give a little thanks to such a wonderful man, and make a wish for yourself to have YOUR dream come true. I will be saying prayers for you, and I have to let you know - you have ONE TERRIFIC ATTITUDE!!! I do understand so much about the months and months of TTC... and let me tell you, I believe it will happen for you, too. PLEASE let us all know when it happens for you. I believe it will happen for you. I have a hunch. 
In the meantime, ENJOY all of the thrill rides and go on the ones you may have missed due to fear, in the past... nothing can stop you now! And when you are done your Disney trip, there will be more good to come. I have faith. Keep hanging in there. I feel sad for you too, now, but I know, when your time is here for you to have a little 'un, it will happen. 
