Class A's span a wide range in pricing and configuration, quality. For nice/entry I'd suggest a Jayco Precept. A lot of the common Class A's all ride on Ford's F53 platform, many of them gas V10's, newer ones come with a V8. Not a bad chassis at all.
The killer for me is access to engine, and not having cab doors for easy entry/exit while driving. I just like driving a truck, not something that feels like a living room with a bay window.
If she's stuck on a C, but you want to go bigger than a Ford E-van chassis, I'd suggest a Super C. That's the route we went. It's the next-size up C, on a heavier duty commercial chassis that can carry more weight and is just bigger - including room for driver/passenger. We have an '06 Seneca, which is getting pretty old, but they did make them through 2009/2010 depending on how old you're willing to go. Based on a GM c5500 chassis. Newer Senecas (2011+?) come on a medium-duty Freightliner chassis, like you see box trucks running around with the Freightliner cab. They are fairly modern, diesel, very strong. You can also go with a pickup-truck based "Super C". There are some builders who do them on a Ford F550 chassis cab, or Ram 4500 chassis cab. There's one or two who are using the modern GM C5500/Kodiak chassis which is now the Silverado 4500/5500.
But they're not cheap. Whereas you used to be able to pickup a brand new Precept for nicely <$100k, and a decent brand new Super C for <$160k, prices are just insane right now. It's a crapshoot in terms of what you might find used.