Dan,
My Super Snap Track was not Stainless Steel, I do not know if they ever really made any. I do remember a special K-0690 lock on, however we never used it and soldered drop leads either under or right to the side of the SS Track.
Your post War engines and rolling stock will work perfectly on K-Line SS Track.
Availability of the Track will be a problem, no doubt about it. RMT might have some Super Snap Track, never looked into it myself. I would definitely check with them for availability.
PCRR/Dave