Helpful hints and tricks and all questions answered from previous posts:-
If you're contemplating using gems to finish the horse track, it is MUCH CHEAPER to speed up the track. It starts at 6 gems and goes down 1 gem every half hour. This is much cheaper than buying an individual banner or ingot at 20 and 25 gems each respectively.
Is it worth upgrading or having? My personal opinion is anything that multi drops items is worth it. Is it worth having if you need to spend more than say 30-50 gems? Probably not. You can get the drops from other sources, so not a catastrophe if you don't finish. Disappointing, yes, disadvantaged, no. (But that's just me, others might have a different opinion)
If you can upgrade your track to level 5 then Step 8 slipped by unnoticed. It did with me. I did check with S8 and everyone who said they didn't do actually did.
If you have the last 90 banners and ingots but not carrots or hide, you can still upgrade the track once you have these items. The upgrade button will stay available.
Banners and ingots stop dropping once the event concludes as will horseshoes. You can only purchase them with gems once the timer stops. You can do this at anytime in the future.
The finished Horse Track does drop XP. Will have to check if coins drop once event concludes.
I hope that this summary helps. I'll put it in post 2 as well. Good luck to all!