A wonderful experience for them !
We would love to know how their first big adventure turned out and look forward to hearing. If, before they hit the road, you or they have any further questions ,or would like a little help with planning, let us know. I would encourage them to sit down together and study a good map of the US and find things that appeal to them and how they can work them into their trip. They do not need to be tied to one or two route numbers, they have time to explore, whether it be the St Louis Gateway Arch, or the Grand canyon, or any one of thousands of other possibilities.
It would be advisable to keep their daily mileage to no more than 500-550 miles so that they have time to rest and relax along the way without getting over tired. With 2 weeks they will have time to take a day off from driving 'here' and 'there' and have shorter days behind the wheel. Every place they go to is someones home town where people live and work and raise families safely. If they use their common sense as they would when out and about at home they will be fine. Usually if the 'built in radar' that senses something does not feel quite right, it usually isn't and it's best just to move on until you feel comfortable.