Indeed. As I'm sure you know, there is another sign facing the other way about 100 yards downhill from the entrance to the Park. That one isn't as photogenic and it forces you to park your bike nose down, and that is something to be avoided.
Surprisingly, I can't recall ever seeing anyone else stopping there for a photo op. Maybe my timing has just been bad.
Once you rent one I'd definitely like to hear your opinion on the Spyder. I haven't ridden a standard MC in 20+ years so I don't have a current frame of reference to compare the two. All I can warn you about is that the steering is going to throw you off at first until you get used to it as it's nothing even remotely close to standard. Counter-steering? Don't even think about it.
I didn't notice the speed limit. I'm not much of a speed demon so while I may be a bit above the speed limit I'm not particularly noticeable--especially when the sportbikers in full leathers are charging around.