I use lots of cedar here in the local Austin area. There are lots of theories on how to remove tannins/sap from wood but in my experience there is only one way that works in the amount of time I'm willing to wait. I let nature do it for me. With cedar, it may takes 10 years or more but nature has patience down much better than I do.
You mention the lakes. If you have a boat, you got it made right now. All the lakes are low and there is a ton of wood on the shore that is ripe for use. If you don't have a boat, you just have to work a bit harder to get to the good stuff. Do some searching on the mapping sites for good spots and then go trekking. I use Google maps and zoom in on the lake shore. When you can see wood piled on the shore from aerial photos, you can be sure there is a bunch there you can't see. The good stuff hides when planes fly over!
Since we often have South or West prevailing winds, search along the North shore first. Once you spot several likely spots, find a nearby place to get to the water and start walking. Take a small folding saw along to cut those special nice pieces that are too big to drag. Find something that is still solid, not rotten but fully dry. No bark left for sure!
If you cut an end off and the wood is a uniform color all the way through, it is dry and you likely have a winner.
If you want cedar, go way back up away from the water where wood may have been there 15-20 years and you will find Mother has taken care to remove the tannins. There is every type, shape and kind out there.
Cedar that is fully dry.