It would take approximately 11 hours to drive from Houston to Amarillo. Give or take a few depending on how fast you drive.
how long would it take to drive from san antonio, Texas to Boston, Massachusetts
About 15.5 hours.
I don't understand what "at" is.
2-4 hours
It is 277.70 miles according to MapQuest.
4 hours
It will take about twelve hours fifty minutes to drive the 716 miles.
About 2 hours 15 minutes
1 and half hours - 2 hours
Approximately 24 hours.
Google Maps estimates the driving time as11 hours and 45 minutes.