I told you I would provide you with some route info when I got back from Oxford that might help you in your future travels up north. If you recall, I didn't want to go through B.R. and fight that 5:00 o'clock traffic on a Friday, so I took a different, unorthodox, route to Oxford (actually we stayed in Grenada).
We departed Lafayette around 3:30 PM Friday and I started my calculations when we got to the I-10/I-49 intersection at about 3:55PM. The route I took was North on I-49 to Alexandria/Pineville, then east on LA 28 to Ferriday and then north on LA 65 to Tullulah,LA. From Tallulah we headed east on I-20, then north on I-220 around Jackson to I-55 and then to Grenada.
That route is approx. 380 miles from Lafayette to Grenada, MS. My actual driving time was 5 hours and 50 minutes. However, I did have to deal with about a 10-15 minute delay on LA 28 east of Pineville when a State Trooper pulled me over and informed me that I was driving a little too quickly!!!!
Although this was a more scenic route that took me through some parts of Louisiana that I have never seen before (and don't really need to ever see again), I think staying on US 165 to Moanrow would have been just as fast and would have kept me on 4 lane roads most of the way.
We came home on Suday taking the traditional route down I-55 to Hammond and then I-10/I-12 back to Lafayette.
My conclusion: The traditional route through B.R. is the best route as long as you don't get caught in heavy traffic in B.R. or run into trouble on the basin bridge! If you want to avoid any of those possible issues, going north to Monroe will add about 30-40 minutes and about 45-50 miles to your trip, but you can keep moving (unless a Trooper stops you to say hello)! LOL!!!
I hope this will help you in some very small way!