Thanks again all. The Lionel 19109 series cars look very nice and several cars and sets are on eBay right now, so they seem like my best bet. I REALLY like the 15312/29152 sets and I may just set some money aside and be patient for them to come up on eBay or here FS. The 15” MTH cars also look like good choices.
As I expected, you all came through and gave me exactly the help I needed. You also got me to thinking that since my track investment so far is minimal, maybe I should move up to larger radius curves.