Hello, I would appreciate advice for travel from St Charles Mo to Greenwich Ct area avoiding mountains as we are terrified to drive steep inclines. Thank you.

The most direct route, on I70 to Cleveland, then I76 through PA has no steep inclines or declines.

Just get on I70 and head east to NYC and on to Greenwich. The part through Pennsylvania is the PA Turnpike. there are no steep grades or mountains. It is hilly but not dangerous.

Above--I 70 doesn't go to Cleveland

Get to I-80 by taking I-71 from Columbus to Akron OH. Get off I-80 at Parsippany NJ to avoid going over the George Washington Bridge and through the Bronx. To me the Bronx are more scary than any mountain I've driven over. The PA Turnpike has a big tunnel through a mountain. I-80 is toll free through Pennsylvania.