Then this is your life and if you want to go on the Fantasy, you'll be driving? If so, you have your answer. We all have various constraints in life. Yours is possibly no flying and no other land options other than driving. Unless you wait until next year when DS can get his licence and help drive, this is it. Go. Enjoy. Work with what you have. You don't have to cut yourself off from things you want because they are difficult, just plan and manage your time driving. It'll take more time, but take the breaks, stop for the night, or two. Unless that's not viable for this trip, then I say take the Fantasy... do look in to renting a vehicle, though. We rent from the airport locations, as they can be cheaper, but if you're a Costco member, price check a variety of areas. What you spend on rental of a new vehicle may end up being less than the fix on your vehicle during or after the trip due to wear and tear or just for the next oil/brake change.