Will,
I do agree one option is to get a decent locator and a handheld GPS. I also know alot of the lakes you fish and know that most of their maps are available on the Navionics South chip. Zorinsky, Wherspan, and Walnut are all on the chip. One of the least exspensive units you could get that would be compatible with the Navionics chips would be the Eagle Fish Elite 642 iGPS. It runs about $550. Then you would add another 100 - 150 dollars depending on whether it's an '07 or '08 chip.
What I would do in your situation is this:
I would probably buy an Eagle Fishmark 480, which I think is a great locator for the money ($200). I would then get either a Lowrance iFinder H2O ($169), or an H2Oc ($269), both of which are compatible with the Navionics chips ($99). Then you're set. You could save waypoints, find dropoffs etc. faster, and locate fish.
Hope this helps,
Jay