Going Hwy. 45 out of Jackson is about the same miles to Panama City as going I-65 route and only 40 minutes longer. If you do go I-65 there will be a few miles through Birmingham that is very rough, put both hands on the wheel and hold on for about 12 to 14 miles which may be a good reason to go Hwy. 45.
If you do go I-65 a decent stop over south of Birmingham is called Birmingham South RV park in Pelham, cost about $40.00 a night, just a mile off I-65. Would be about 240 miles from Jackson.
If you were to go from Corinth on Hwy. 72 and get on I-65 at Cullman, AL there is a good stop over campground called Cullman Campground about 3 miles west of Cullman and only $25.00 per night FHU. This would be about 170 miles from Jackson.
2014 Cedar Creek 34 RLSA-7
2015 Chevy Silverado 3500HD LTZ SRW