Do use maps routed especially for bicycling. State DOTs have them. Some roads are really NOT GOOD for cycling, e.g., highway 190 in Louisiana east of Baton Rouge, and some are very EXCELLENT for cycling, e.g., highway 190 in LA west of Baton Rouge. A properly mapped out bike route should steer you along the better stretches of road.
Louisiana's DOT will run you along highway 90 into New Orleans where you can get on the sine-wave river road to highway 77 which will deposit you on highway 190 west of Baton Rouge going east to west. If you have cycled 190 west of Baon Rouge and east of it, you know the good sense in avoiding 190's eastern stretch, especially during the white-flight rush hour when every redneck with a loud, dirty, noisy muffler, bad attitude and a driving problem converges back on the boondocks from the big city, and always when your road shoulder has disappeared.
Mapped bike routes can make a positive difference in your cycling experience.