There was a post-bacc program in my area, but I chose to do it on my own at a 4-year state university instead. I found it a lot easier as a non-traditional (...older 😉 ) student to get to know my professors and to get time with the people in the pre-professional committee, which made it pretty easy to get recommendations when the time came. I was able to form a support-network with other pre-med students in the classes I was taking, and I saved a lot of money -- so for me it worked out great.
With the budget problems that a lot of state schools are having recently, though, taking classes ? la carte is probably going to get a little more difficult. From what I understand, it's getting harder to get into the class sections you want/need (less sections offered), and as a non-degree-seeking student you're usually at the bottom of the registration totem-pole which further lowers your shot at good class picks. Also, with some classes only offered in the fall or spring, you might find yourself waiting a year to get into a pre-req you need (organic II was only offered spring semester where I went) or scrambling to find it at another school. Doing the pre-reqs on your own is do-able, you just need to be a little more aggressive in your planning and execution than you would in a tailor-made program.
Good luck! 🙂