Louisiana's not bad. Never had a speeding ticket on I10 (usually going 90ish) and I did back and forth from Nola to Houston constantly during college. Agreed on the Buc-ee's. I'm sure google will tell you the same thing, but make sure you take I12 once crossing into Louisiana to avoid going south into Nola. It'll take you straight to Baton Rouge.
Worst, most mindless drivers on the face of the earth however. I almost lost my mind driving from Meridian to Dallas on the first day of our move as about the 500th person that I passed sped up and paced me in my blind spot for 20+ miles (or passed me and then slowed down forcing me, in cruise control, to re-pass). Have had similar experiences every time I have driven in Louisianna, with the exception of I-59 which is basically MS anyway.
Aside from this leg, I didn't find the trip down I-20/I-10/I-8 to be too bad. Whole lot of nothing as I'm sure you are aware. Stopped in Dallas, Midland, El Paso, Tucson, and arrived at Miramar last night. Enjoy the 80 and 75 mph speed limits through most of W TX and NM/AZ. There is a lot of construction going on in AZ with reduced speed limits, and I found their police to be the most vigilant of any of the states we passed through, as well as having numerous camera/radar traps through most of the state (they are however clearly marked a half mile or so in advance). There are several border checkpoints you will have to pass through in western AZ and most of eastern CA. Not a big deal, but that can slow things down depending on the time of day. I don't really think you have too many other reasonable options going JAX to SD aside from I-10/I-8, but like I said, it wasn't bad.
