Welcome to the site Newbie
. Yeah, its fine to mix octanes. I run 44:1 with no troubles for years. I recommend synthetic 2 stroke oil, and stick with one brand. W D is not oil. It is actually corrosive. Run the bike for a few minutes to warm chain and clean it. Head back to the truck and use a chain lube. Or I usually spray the chain down right after I wash it. It is less messy if you lube chain by spraying the chain in the chain guide. I always use NGK B8ES. Don't forget to turn off gas. Like Cam is saying it can cause problems from bouncing around then flooding the bottom end. I also use the Uni air filter with No Toil.
Sometimes a bike will foul plugs at start up, when the floats are out of adjustment. Its called cold fouling, I think. The easy cure is to run it low on gas by shutting off the petcock before you kill it. The right way is to set the floats to shut off sooner, but I think thats where that idea comes from.
There's a bunch of good info here, especially the straight fender mod, jetting charts, tire dicussions, pipes, fuels, and even some for entertainment only. Check "Best 500 I've ever seen"
Oh yeah, you need that mud flap. Rear shock repairs are not cheap.