Don and Mike, I have been considering the Atlas option. Going the Atlas route with 70T RB trucks and Kadees is definitely a viable option, especially since I could sell the old Lionel trucks off- 3-rail guys do love them and I agree it wouldn't be too hard to sell them. The issue would be finding enough Atlas trucks- like everything else it would take a little bit of time, but that's okay.
I was working in Oregon last summer and while I was away, my wife decided to "organize" my train collection- I went to inventory my Husky stacks, and of course some were missing. So it turns out I had bought a few sets I didn't realize I had- I missed a few road releases, but I'll pick them up on Ebay, at a train show, or even here. The best thing about this hobby is you can pick up where you left off.
Geno