1997 Suburban , weight

Hello everyone,
 
New to this forum and fairly new to working on cars.  Unfortunately I did not spend my teen years rebuilding carbs like my brother, so I feel like I am starting way behind the curve.
 
Problem: 1997 Suburban is a nice comfortable vehicle for my wife and I, BUT with its weight etc, the MPG is horrible.  So, is it possible to trim down the weight on this vehicle to eek out a few more MPG? 
 
I was thinking of trying to turn it into a 2 wheel drive, and wondering how much weight could be removed by loosing the front wheel drive mechansims.  First is such a modification possible, and secondly would it actually save me any fuel?
 
I really like this vehicle, interior and all, but at only 12-13 mpg, it needs some fixing so I can afford to drive it for work related trips.  (Road trips to sell products I turn on my lathe)
 
Any advice would be welcome, even if it is "YOU idiot, you cant get MPG out of that tank"  LOL.
 
 
Thanks,
 
Darin

without spending money i think the only signifcant weight to lose would be the front drive shaft. maybe 50lbs. the 4wdr aspect requires a heavy tranfer case and front drivetrain but you cannot just rip them out cause they still drive your boat. let alone taking off components whatever they may be could throw some computer stuff out of whack. i also own a 97 boaturban so i feel your pain. Or 3rd bench 80lbs., and spare tire( bad idea). option 1. 2wdr. suburban. plenty out there usaully law enforcement. 2. upgrade/tune  what you have. quality ( but not expensive performance grade ) plugs, wire, cap, rotor,  air filter,  good frequent oil changes, tranny differential.  keep your fluids fresh.  crapped up fluids cause resistance and  more work  for the same effect.  tire pressure.  dont ignore oxygen sensors they tell  you if your  wasting fuel in the mixture. also keep your engine cool. an full change to an electric fan takes a load off the crank but you might need to get a HD alternator, maybe not. along those same lines different serp belt and dont run the A/C compressor again a lot of  load on the motor. if you have  the 42 Gal tank and your not traveling far dont keep it filled that's alot of weight to be needless caring around. At 70mph your rpm should be at about 1800-2000. if your higher its more fuel and possibly a tranny issue not shifting into overdrive. sounds stupid but make sure your not driving in 4wdr that kills it to. sorry if thats ignorant  but iv'e seen it done.  those are all the ideas i have some easy some extreme good luck. i have a 97 w/ 130000 and she gets about 15 city.