Be aware that LED light assemblies not only last longer, they use less energy! That may be a problem with old bi-metalic flashers that need an energy hog of a light bulb to heat up the bi-metalic metal strip and make the turn and hazard lights flash!
If you want to refit to LED lighting at a minimum of cost, May I suggest a trip to your local junkyard? New parts will cost you. Surplus or junkyard parts can make this a fun, inexpensive project!
What is the energy savings? My rough guess is 1/10th-1/20th of the energy in one 50 pound battery. So it's a nice final tweak and it's cool but it won't make a significant difference in your range. Improved aerodynamics is a better return on your investment. At the same time, every little bit helps. Also check out High Intensity Discharge (HID) headlights. Much better, much lower energy requirements and rather expensive!