(1) Buy a week with it's limitations and take your chances on using it.
Buying a week at any other resort won't help as he can't exchange in via II, or within MVC without electing points and using those to book there. And again, you can't buy just a week at a Ritz Carlton, he'd have to buy a fractional interest, which is VERY expensive both in terms of purchase price, even resale, and MFs. For MFs, not only are you paying for multiple weeks, you are paying for multiple weeks that come with the cost to maintain Ritz Carlton brand standards, both in physical quality of the buildings/units/furnishings, and service levels, which really are very different from your normal timeshare, even at top tier brands in the timeshare industry like Marriott or Hilton. And even if you own a fractional, you don't just reserve the specific week you want, each year you are automatically reserved for the weeks on your rotation for that year. I do understand that there is an internal Ritz exchange system, but it is not quite as robust and flexible as what we are used to via our normal timeshare systems and/or II, as there are far fewer resorts and, especially for prime weeks, far less likelihood of other owners relinquishing those weeks when it's finally their turn to have them.
(2) Acquire a reservation using points.
This is what I do (using elected points, I don't own any Abound trust points), and what the OP is trying to do. But again, for the Ritz locations that don't have much/any inventory in the trust, it is extremely difficult to book even for non-prime weeks. Owners are less likely to elect to put their weeks into Abound unless it's a truly undesirable time, as they can get better bang for their buck by renting out or exchanging in ThirdHome for other luxury properties.
(3) Rent from an owner that has the desired reservation.
A little less difficult than using points at non-trust properties, but like option 1, VERY expensive most of the time. As in, "typically much more expensive than MFs for the underlying trust points to make an equivalent booking in Abound would be" expensive.
Not sure what you mean by rent through MVC, unless you actually mean the non-timeshare website run by the hotel company (marriott.com). If that is what you meant, also extremely expensive. As the OP mentions in post #13, they can't or don't want to spend the kind of money for the normal ways of booking at a Ritz Carlton.
(5) Use cash to rent an equivalent unit in the area.
Extremely unlikely to find an equivalent (we're talking Ritz Carlton here, which means both luxury accommodations and luxury service to go along with it) that wouldn't also be prohibitively expensive.
Overall, as nice as those stays are most people aren't going to find it worth the cost (or can't afford it), either to own a fractional interest or in the Abound points it takes to stay at those properties. For the most part, I'd rather have multiple or longer stays elsewhere. But every once in a while I do find it nice to treat my family to something a little different and "extra." If you do have the opportunity, I recommend checking one of those properties out even if it's just once. It's a very nice experience, even if you then decide it's not worth the cost in points to stay there again in the future. It's especially nice for special occasions. For my family it's been short stays for an anniversary and for birthdays. The ones I've had so far have been within the period where I got a points discount for being close in. But because my daughter requested it for her 21st birthday, I booked way ahead for Ritz in Vail for next year. After that one, I probably won't do it again unless I see something at the Ritz Aspen or Ritz Tahoe during a time where I can get there on short notice, just because I'm curious to check out those locations for a couple of nights.