Late October Interstate highway driving is 90% no problem. It pays to check the forecasts when crossing the Rockies and Sierra’s that time of year…something I get the feeling a honeymoon couple might ‘forget’ to do. Mt Rushmore should be OK. Grand Canyon is a no brainer (South Rim only) it is always open. The North Rim usually closes for snow by Nov 1, so it could be more difficult.
Monument Valley is beautiful in the Fall, as is the Canyonlands area. Desert weather may be brisk, but not wintery at that time of year.
If I were asked for serious advice about this trip, I would suggest either of the two following alternative plans—
1. A flying-Honeymoon to San Francisco. Fly out and back and get a package of hotel and car to give you several days in California for sightseeing…Napa, Yosemite, Redwoods, & The City.
A quick look at Travelocity on AOL gave me over 30 trip/hotel options for 10 days and 9 nights ranging from $750-$2000+(per person) using non-stop flights from STL to SFO. Car would be extra as would breaking up the nights for different hotels. But that is still fairly inexpensive travel.
2. A roadtrip to Mt Rushmore then thru the Utah national parks to the Grand Canyon then home…no California segment. Still a lot to see and drive, but two weeks on the road might be doable. The weather could have an impact on this in the Rockies on the way out. I-40 on the way home would be no problem. This would be cheaper travel and certainly less crowded, but they would mis San francisco…if that is important to them. A lot depends on whether they enjoy driving and ‘nature’ sightseeing, as opposed to city-visiting?????
Please do keep us informed on your planning progress..