“As we are Planning a stay in Rome (3 days) and in Tuscany (1 week), we would also like to visit Assisi, in Umbria. Does it require a day trip from Tuscany?
Visiting while driving from Rome to Tuscany could it be an option?”
Assisi really deserves a full day.
So better if you drive from Rome to your destination in Tuscany, and eventually pick a nice day for your trip to Assisi.
It is possible to do as a day trip from Tuscany, however also consider to stay overnight there to enjoy the magical night of Assisi.