Too old to continue traveling ? Grown children urging ..

The next time you are over, pull out a measuring tape and go to the master bedroom. When she asks what you are doing, just tell her you are measuring it for you new furnature. Since she is so concerned, obviously, she doesn't want you very far away. ;)

Seriously, if you can honestly say you are fine to drive and no serious medical issues, politely point this out and move on.