Having no way to camp, and relying on the shelter of motels or hosts might put you in uncomfortable positions from time to time. Your planned destination for any given day may seem easily enough attained where mileage is the only concern. Mileage is only one variable. Strong winds and or rain can put you off your bike for hours making the day's planned stop beyond your reach. I would say you could probably do the southern tier the way you plan, relying on motels and others for shelter every night or so. I would also say I have done the ST 5 times from Florida to California, and twice from Florida to El Paso, Texas. Many times storms, wind and rain sent me off the road, sometimes all night, sometimes for large parts of the days. Being out there day after day, week after week might put you in the way of lethal weather events. In fact, it is considered a small miracle I am still alive, what with the many instances of massive bolts of lightning slamming to earth all around like a concentrated military barrage. You could have excellent weather like I had on one crossing, and you could be brought to a dead stop by wind and storm. It is a matter of possibilities. I always camp most nights, and stay occasionally in motels. In a car it is one matter. The power and shelter conquer wind and rain up to a point. On a bicycle the weather has much more control over you than in a motor vehicle.
