RX,
Responding to your initial post, I'll base my input one 1) having from new, a '95 Camry V6 with 190K on it, and 2) having just purchased its replacement, a '01 RX 300 with 88K on it...
The Camry has been a delight in terms of reliability and value. I'd vote to keep it, however elderly parents dictate we drive something that is at a more favorable seating height for orthopedically impared adults.
I purchased both vehicles with the intent of driving them to 200K or better, so I've not scrimped on maintenance. I kept the Camry under dealer maintenance until 120K, when I found a local independent that was better and less expensive... by about 60%. Being a former military pilot, I'm of the mind to replace things BEFORE they fail.
Items I think you can expect to need between 130-180K:
CV joints/boots (if you're changing the boot do the CV, too. The labor is sunk cost. Did mine at 140K.
Struts. Did all four at 175K. Turned it into a new car. KYB vs OEM. Wifely driver is usually mechanically oblivious unless the car won't go or is shaking to pieces, but called me on the way home from the re-strut/rotate/balance to exclaim what a difference it made. Well spent $1000.
Engine mounts/dogbone replaced ~120K as a collateral premptive repair whilst doing the timing belt and replacing (yet again) the valve cover gaskets.
PS pump and rack @ 150-160K. High pressure hose anytime after 80K... may go to eternity, though.
I'm of the opinion that almost any TMC product is easily capable of going 250-300K if routine maintenance is done and worn consumable parts are replaced in a timely manner that prevents collateral or cascade failures. It's the little 'penny wise' items that will clobber you... e.g. worn/bad dogbone will stress the manifolds, exhaust headers, engine mounts, half shafts and seals, and steering components.
I share your concern about the basic V6 Camry chassis hauling around an extra 850-900 pounds under the RX300 and intend to pay particular attention to the transmission and the brakes.
I'm a tightwad, too, and receive a lot of skeptical comments from my coworkers and family who can't see why I'd put $1000-1500 in maintenance into a 10-12 year old car to keep it highly servicable.... Simple, $1000 is something like two car payments if you include the increased insurance and taxes. So, if I can avoid a $30+K purchase for six months on that grand, I think I'm money ahead. Depreciation is no longer a relevant factor after 125-130K anyway. Now you're running on utility value. I'd vote on spending $4-6K in manintenance over 3-4 years to keep a car you're happy with.
Cheers,
JMC