Valdosta is a good stopping off point. On our last trip, we stayed about an hour south of Valdosta in Lake City, FL. That gave us only about a 2 1/2 hour trip to WDW (see below on why it took us a little longer). Valdosta is a little nicer, but we liked being that much closer.
Easy if you have the points. However, we don't have a loyalty to a specific chain, and neither DH nor I travel out of town on business. I know we belong to a number of hotel programs (Wyndham, Starwood, I think Marriott). We may be close to a free night at a Starwood; I'm not sure. We may stay a total of two nights a year in a hotel room. We usually make it to our destination in one day, and if our trip is more than a day, we stay with family. And we own a timeshare, so we trade into other timeshares for our destination.
What we've done successfully....buy $100 Marriott gift cards at Krogers when they've had their 4X pump perk points. A $100 gift card will save you 40 cents a gallon of gas next time you fill up. With my 13 gallon tank, that's a $5 savings...not much, but every little bit helps. If your gas tank is larger, you'll save more ($12 on a 30 gallon tank).
That's a possibility. At Lake City, we actually stayed about ten miles east of town on I-10. That added a few minutes to our trip. All of the hotels along I-75 were either filled or was charging $200/night. That was because Florida State was playing at home that weekend, and a lot of Seminole fans stayed in Lake City. And Lake City is over 100 miles away from Tallahassee.