As a Promo Rep, I like most of the calculations from @jayski except for the lower Nautique calculation. Forget about how the rep gets the boat or how much he pays for it. Assuming your other calculations are good (and I think they probably are), put the Nautique price/hr in there with the others similarly or same. Pay the mileage, allow the free entry fee for the Promo rep; in many cases the promo rep may be an official, thus you can comp the room (this should be done anyway), and see how this goes. For now, remove the Regionals & Nationals from this scenario.
Note: A flat rate per boat/tournament may be OK if there is >1 boat and boat usage is even to a degree. If I bring a boat, I don't want to be the only boat pulling the event. If I am the only boat, the hourly rate would need to apply. Last, let's see what solutions or incentives that USAWS may come up with.