18 trips back and forth to Beaufort, 1,100 miles each way. Me, Kathy and the two Jack Russells in a 4-door diesel pickup. 16.5mpg towing the trailer, 38 gallon fuel tank. The math says 600+ mile range or one entire driving day. Would always do 600-700 miles the first day, 6-7am start to 5-6 pm stop, usually including no fuel stops, lunch stop (we shared our sandwiches with the pups) and two puppy/adult breaks. That would usually get us through the Washington DC rush hour traffic (which was ALWAYS awful on the Beltway, especially hauling a trailer in heavy traffic) by the end of the first day. Jersey/Philly/DC traffic was why we moved inland to I-81. 100 miles farther, exactly the same travel hours.
Second day, out by 5:30-6am (usually couldn't sleep well in hotels), fuel up ASAP and then morning puppy break, noon lunch stop, 2pm puppy/adult break and home by 3:30pm.
Trip notes: Service stops almost anywhere outside of New England are great - PA north into New England they pretty much suck with New Jersey and Connecticut vying for the worst on the east coast, especially if you have dogs. There is at least one Virginia state cop per mile on I-95, starting 15 miles from the state line, to the state line (both north and south) - all with RADAR. Georgia has no service/rest stops remaining on I-95, either direction. They may have eliminated their "Welcome" stops by now. SC has the lowest gas/fuel prices and they usually increase 15-20 cents per state as you drive North. The motels along I-81 in W. Virginia are reasonably nice - the people are a little weird. I will always trust semi-trailer drivers WAY more than I will ever trust a car/pickup driver. The federally illegal "Speed Trap" on I-95 in Ridgeland, SC (just north of the Georgia state line) has been eliminated and physically torn down by the Feds. Before the Feds took Ridgeland to court (and won, stopping their issuing of tickets on a federal highway) the town was getting ticket revenue upwards of $600,000 per year for 2 - 3 years.
I love driving - it's the "getting there" that's boring.