Yup, that's basically what most of the CT125 type adventurers have pointed out. Shipping is a huge cost that usually dwarfs the rest, particularly if you're shipping both ways.
In my case, I'm shipping one way only and committing to riding back.
I have a spreadsheet tracking my expected expenses with a pessimistic view on most of these costs that you can look at for individual costs. That's assuming I have all the swag I need for this already (I almost do, I would need some clothing), and costing only fuel, accommodation, shipping, flights, and necessary maintenance.
Right now the magic number is $3k, 1/3 of which is just getting the bike to the start line, and assuming we have a pretty luxurious time along the way.
EDIT: Side note, but at one point I was cost estimating based on what it would take to get my bike back from Vegas to Seattle via various mechanisms. In the end I went with a $670 U-Ship. I have that data saved still complete with a data visualization and can share that by DM if you're interested.