Sorta depends...if you're a planner and like things your way, solo is the best route. New things begin an adventure. Going into the unknown can be scary at times.
That said, if you'd rather let someone else plan your trip, do the homework and all that, then take the tour route. That's what you're paying for. Your comfort zone is secure because you're traveling in numbers and if something breaks, you'll be secure in knowing someone's around to give you a hand.
All in all, it's your decision, your comfort zone and how you can get the most out of your trip. Lots to see and do up there, and lots of side trips, etc. We don't like interstates and prefer backroads and off touristy sites. If you're like us, you probably won't like the caravans.....Dennis