Hi,
I have driven from N.O., LA several times and we generally make Tallahassee about 6 hours into the drive. I have stayed at Holiday Inns and Comfort Inns (just pulled in when locating one while driving on I-10 - both going to WDW and coming back from WDW) while overnighting there and have never had an unkempt room. Usually, I believe that if you check in after 9:00 p.m., the room amount drops a few dollars. The few times that I have done this I have managed to procure a room from $50 to $60 for that night just by pulling up and asking a little after 9:00 pm. If you definately want to stay in Tallahassee, then check out a site called biddingfortravel. This is a sister type site for priceline. The site is great, you scroll down the first page until you see the state of Florida and then click on the area. People post what hotels they won on priceline, the date of their stay and the amount that priceline accepted. If you definately want to stay in Tallahasse, I would attempt to bid for a hotel in that area. Otherwise, if you are seeing how far you can make it before getting to tired, then just check into a hotel chain that you now you like along the way but make sure it is after 9:00.
Hope this helps.