djhofup,
to the forum from downstate. It looks like your new trailer is going to be sitting in the snow for a while yet along with many of ours. The forum is a great way to gain knowledge about Keystone RV's, camping and maintaining them and in RVing in general. We're happy to have you join us and we hope you'll share your experiences as you learn about and use your new Springdale.
The trailer ball is a 2 5/16ths, but there are many grades of ball that size. Your Springdale has a GVW of 9500 lbs, so make sure you get a trailer ball that's rated at least 10K. Many auto stores have trailer balls that will fit, but they are only rated at 6K or 7K. The last thing you want is to snap a ball shank while towing something that big !!!!!
Again, welcome and enjoy your time on the forum.