Well, to get to Athens you're going to have to have a car anyway, because any other route would be extremely costly.
And when you get here, you need a car to get around.
Although the center of Athens is quite large compared to the surrounding areas, most of the roads are one lane. Therefore, getting behind a slower, elderly person (or any age really) can be hell. Remember, you can pass if the yellow/orange lines are broken but if they are pure colored you may not pass.
Also, OBEY SPEED LIMITS! Police in the area don't make big money because they don't have the big numbers to give tickets to. So, they make their Christmas bonuses off of speeders. And, trust me, when no one is on the road the temptation is there! Be very careful!
By Car : If you are travelling from Dallas you can take I-45 south through Ennis to Corsicana, then take Hwy 31 into Athens. Or you can take I-45 south, then US-175 east to Athens.