You're not going to prevent moisture getting in those lines, period. There's a reason you have to pull an AC system down to a hard vacuum before putting refrigerant in; it's to get all the moisture out.
My point is that if you're going to eliminate the AC system, get rid of all of it, including the lines.
Also, I'm not sure how high of a level you are, but I wouldn't be able to notice a 35-pound weight difference. Now, if I'm converting a car to a full-on race car (no longer street legal), then heck yeah I'm going to ditch the AC (and a bunch of other stuff). But if you still drive your car on the street, I'd leave the AC in.