Austin Texas to Fayetteville Arkansas

Sounds like you are not in a particular hurry. Based on that assumption I would take US 79 from Austin to US 59 at Carthage. US 59 to Texarkana. Then US 71 to Ft Smith and I-49 on up to Fayetteville. Been a lot of years since I have been on those roads so maybe someone else can comment on current conditions. But that gets you thru much prettier country than taking the faster route of I-35/US75/US69/I-40/I-49.

There are also a number of other options for going thru east Texas and either western Arkansas or eastern Oklahoma that others can comment on.