We live between Anderson and Pendleton, Indiana. Christmas 2014 we went to Port St. Joe State Park in Florida (South of Panama City). We too 3 days to get there and drove straight home at the end. From (North of) Indianapolis, we planned driving 6 hours (down) for 3 days. We did not want to beat ourselves out and be exhausted once we got there, so we enjoyed the journey!
For our first night, we stayed at La Quinta Inn at Goodletsville, Tennessee. They had a really sweet RV and Bus parking area behind the motel, and pet friendly.
If you stop near Fort Wayne the first night, this would give you about an 8 hour drive your second day. When we were there, temperatures were cold, but not as cold as Indiana. But we planned this so we would not have to de-winterize yet.
The second night we stayed at the KOA at Ozark, Alabama and de-winterized. The third day we made it to the State Park. We arrived fresh, well relaxed, and in good spirits! Had a great time.
I'm not sure about motels in Fort Wayne, but I am sure there are plenty to choose from, and if you call ahead, just ask about RV parking. That's what I did with La Quinta before booking the reservation. We stay in motels only 1 time a year (and only 2 times in the last 2 years), and both were when we were on our trip to Florida over Christmas (2013, and 2014).
I, for one, would not want to de-winterize anywhere in Kentucky until the first of March or even Mid-March.
FYI... State Park campgrounds are open in Indiana during off season. There are no gate fees either. You just pull in and pick any spot to camp. DNR will come by your camp site to collect the (off season) camping fees. However, you will also NOT have water anywhere, and the bath houses will be closed. We visited Summit Lake State Park last week end and the put port-a-potties outhouses outside the shower/bathroom facilities in the campground. You could still dump at the dump station too, but no water to flush anything.
So, if you don't mind skipping a shower for a night, you could always stop at one of the State Parks near Fort Wayne. Just an idea.