Hi John -
I don't know what kind of impact the test change is having on scheduling - someone who has recently tried to register might be able to offer more insight than I can - but I wouldn't stress over that point too much. I would be surprised if you couldn't find something that worked for your schedule if you're planning this far in advance.
As for the simulator - I would definitely recommend it, as it does a really good job of approximating the real exam in my opinion. Like others before me, I found the questions to be just a notch or two harder than the real thing, which was great because knowing that I could routinely pass the practice exams gave me plenty of confidence heading into test day.
As for whether you should go with ONLY the simulator ... that I would question, if only because it's putting all of your eggs into that one basket. Sure, test-taking skills are part of it, but I've always been of the mindset that knowing the material is much more important, as is the confidence that you bring into the exam knowing that you know your stuff inside and out. The simulator will definitely help to bring those things together and get you used to the testing environment, but you want to make sure that you have a nice, solid foundation in place first.
I'm assuming from your post that you took a classroom-based course last time around; if so, you may want to consider subscribing to the PrepCast and using that for review. Even if you feel like you have the concepts more or less down, hearing it again from another perspective might help to make new connections, reinforce what you've already learned, and/or help to untangle things you may have learned wrong without realizing it. It's really easy since (for most lessons) you can go the audio-only route during your commute to/from work, and with the cost being as low as it is, it's very little risk for potentially high reward if it ends up helping you with the exam.
That's just my $0.02, but I found both resources to be extremely effective and a terrific value, and worth considering given how much time you have between now and your target exam date.
Good luck!