As for the Sunset Models Amfleet I cars, they are hands down the best Amtrak cars out of the box on the market. The challenge, at least in the short term is the right power to pull them for their 1976 to 80ish early time period i.e. high quality P30CH or F40PH. The E60s were a great idea, but only for the NEC modelers. Personally the P30CH would be neat as they've never been done before in O Scale.
Enjoy some photo mock ups I took a while back on the O Scale layout in progress.