Some other cars you should be looking at are the Toyota RAV4 Hybrid (MPG is 34 city/30 hwy) and Honda CR-V (MPG is 28 city/34 hwy). The Toyota is more reliable and the Honda has a few problems with the infotainment system. The Honda would be my choice because of a nicer interior and driving experience. If you do hwy miles mostly, CR-V is more efficient. These small SUVs are perfect for retired and older people because they are easy to get into.
Or you could get a Chevy Equinox Diesel, but those are overpriced without incentives. There are always incentives though. There is no reliability data on the diesel, but expect it to not be good in its first year.
You mentioned the Prius Plug-In. The Prius Plug-in is the one made from 2012-2015 and it was a failure because it was just a regular Prius that had 12 miles of EV range. The new Prius Prime has a 22 mile range and is a much better car in every way. The Prius is very reliable and can get 60+ MPG when your EV range runs out. The 2016+ is very comfortable. The 2016+ Prius is notably harder to get into than the previous generations.
The Subaru Crosstrek is not as efficient as the Prius and is slow. Otherwise, there isn't much wrong with it. It won't be as reliable or comfortable as the Prius. I would only buy a Subaru if I needed AWD.