For a 737 -700 ,with full fuel load (21 t) ,considering a MTOW of around 70 t , giving you a payload of around 11t you will fly for 9 hrs with almost 3t remaining fuel. The LR cruise speed is around M .785 ,or TAS 450 kts.
With aditional fuel tanks (9 tanks) you may raise the max fuel capacity to 40500 litres (the new 737 -700 ER ) -48 pax for a max range of 5510 NM (10200 km) .Quite impressive.