Well designed kitchens not using very limited no options 3 page spec book stock cabinets are too complex to be purchased online. No company with a 800 page spec book is going to take the chance of working remotely without their certified contractors on site. That's upper end full custom to have a designer name traveling crew come in and do the kitchen. Cabinet companies also have regional territory agreements with dealers to sell only in certain areas.

You need to talking with dealers in your own area. And have a realistic budget for mid grade.

have you brought in samples: I found maple and certain shades of cherry work with the older knotty pine [I have plenty of the pine]. If the pine must remain....and realistically, you might consider painting over it....it will keep some of the vintage feel but the lightening can be a vast improvement...I've seen it. You are considering painted cabinets but seeking entry level or so...don't do that...just don't. You'd be better with good thermofoil . but anyway: there are stains and certain species that work with the old pine....and you can stay entry level if you wish for pricepoint issues. You can paint the pine wall surfaces...or even in partial areas....and then you have a wide array of things you can do. It all depends on budget and the level of scrutiny /change you are up to. An elderly parent can have a "medical event " out of nowhere and then selling time is upon you. Kitchens do not get back entirely what you might think you would expect. What are aspects of the kitchen , that if changed, would actually be of benefit to her . You can put glide-outs in older cabinets, change the handles,etc….if useability is a driving force: all I'm saying is think things over.

Painting the paneling is an absolute no. NEVER. The reality is someone will tear down this house eventually (situated on 11 acres water front property in ME). So redoing the kitchen would be to make Mom happy. Not seeing this project as being about resale. I wouldn't say we would only consider low end entry level cabinets just that buying high end ones is just not prudent.

This would be a good time to look for a kitchen designer who has a CAPS certification. It'll be worth the effort to locate someone who can customize for your mother's needs. There are many threads on this forum that deal with designs for ageing in place.

What is your budget because once you replace cabinets, you will be replacing other stuff as well - counter; sinks; fixtures; probably lighting.

While I agree that people should enjoy their current living situation, realistically how significant a lifestyle improvement will it be to redo her kitchen. Aside from there being blind corners, what doesn't work. There are ways to retrofit existing cabinetry to make it more functional.

Also, depending on her age, how much intensive cooking is she going to be doing in the coming years. Not to be negative, but I have experience with my parents, their friends and some of my aging neighbors and their lifestyle for the most part isn't kitchen intensive so money spent on upgrading their kitchens to modern standards for a home cook aren't necessary. Perhaps think about upgrading to age in place in terms of bathroom as my senior friends cook less but are much more thankful to have bathrooms that are geared to their needs - i.e. large walk in showers; comfort toilets; grab bars; washlets etc.

I am a CAPS Kitchen Designer. I urge you to reach out to a similarly certified designer in your area. Building in usability is no more expensive than building in unusability.