The problem with setting out to ride an IBA sanctioned ride is it changes your view of riding, and thus, your planning of future trips. Nearly everywhere becomes a day ride. Worse, if you plan a multi day trip across the country. Next thing you know, your planning to cross the entire continent in 2 days. Ya, you can, but should you? You miss so much.
So ya, do an IBA ride if it tickles your fancy, but just be aware it will change your riding forever.
See this is where folk set their sights way too low.
If you are planning to "cross the country", then of itself that is a noble ambition .... but San Diego to Jacksonville?
If you are going to take that much trouble, then cross the country properly, please .... Key West to Prudoe Bay
It's very difficult to understand or explain why people do things like this. It's pointless, wastes planetary resources, it is difficult and, some would argue, dangerous too. The preparation turns a great looking motorcycle into something Mad Max would be proud of. Some riders take a $25000 motorcycle and add many thousands of dollars of unnecessary extras, then they ride it until it breaks.
If you ride across the country in two days, one perfectly valid view is that you miss so much. On the other hand, had you spent that two days west of the Sierra Nevadas, then you would have missed Arizona, Texas, Louisiana, Mississippi, Florida ... well you get the drift.
If you ultimately decide to enter the Big Dance, then it's not just 11000 miles in 11 days .... it's 11000 dollars too! And of 100 who are waved away by Warchild, some will not reach the finish banquet, and only one will win. Most are not even trying to win.
Yet we went to the Moon, didn't we? We, as a species, did not do that simply to develop a coating for non-stick pans, or a pen that writes upside down. That might have been fun for the engineers, but I believe the guys sitting on top of two billion dollars worth of "lowest bids", did so simply because they could!