There is no doubt that Trump is the more vigorous and vital of the two, but Hillary has just gone through a demanding campaign schedule traveling and speaking all over the country as well as appearing on national television in three taxing debates preceded by a series of debates in the primaries. There are not many 69 year olds who could stand up to the demands of a year long campaign.
Hillary Clinton is obsessed with attaining the WH. She failed in her first attempt at getting the nomination in 2008. In 2016 she got the nomination and failed at being elected to the Presidency. I see her trying again in 2020. She won the popular vote in 2016 with the third (and possibly second) highest total in American history.
Clinton must be prosecuted and held accountable for her crimes. It is the only way to be sure that she is "finished with politics." Unless we drive a stake thru the hearts of the Clintons, they will remain a divisive and dangerous force in our national polity.