One thing to consider is that OEM shock absorbers are $35 each. They're not terrible, but they're pretty inexpensive and basic components. There's a lot of things that go into a comfortable ride that you likely cannot change or are not going to have the information available without very complex modeling or trial and error - like frequency of oscillation and basic geometry limitations. If you want a really comfy highway ride a highlander or other crossover will do better.
On the 4runner, KDSS does a great job at reducing body roll and also does a good job at stabilizing the body during slow speed offroad situations. It's a marked difference between KDSS and non KDSS in very slow bumpy travel - like rock crawling. But it's not magic. And it does limit your suspension travel and suspension choices.
In my opinion if you want the best all around highway ride quality plus moderate offroad capabilities a Trail with KDSS plus fox/king/?? adjustable coilovers will be a good option. I ran my Fox 2.5" front coilovers at stock height for a long time. You don't have to lift it to run great quality shocks. And the ride was significantly improved. The biggest noticeable benefit was small bump compliance. It took all the harshness out. And they perform very well at medium speed desert type terrain or long washboard gravel roads. It makes a great daily driver and still plays well in the dirt. With my setup I'm currently around +2" for the summer of Moab trips and trying to keep my bumpers attached... but I'll probably drop back down. The ride quality will basically always be better at stock height because the control arms are closer to horizontal meaning by the nature of the geometry they're going to transfer less impact shock to the frame than they do when lifted.
The downside of KDSS is that currently no-one is making extensions to compensate for lifts, so when lifted it's running out of it's normal operating range and doesn't probably work as well. A set of spacers would be easy to build. I just haven't had time to take all the appropriate measurements and send a file out to a CNC shop to have a set make. I'm hoping things will slow down for me this winter and I can get a set made to try out.
If you want to go more extreme I think you'd be best off starting with an SR5 model and putting the savings toward long travel suspension. You're realistically looking at around $10-15k for a full offroad build. There are some really good kits out there that run around $3-4,000 for the parts. There's really no comparison if you want to hammer down washboard roads for 8 hours a day. You'll give up street manners, but gain a lot of comfort in the dirt. Add another $4,000 for front and rear locking differentials and 4.56 gears, $2500 for a "lefty" transfer case, throw some 35" tires on, and you'll have more like the ultimate offroad version of a 5th gen. If you're going this route - don't waste your $ on a Trail edition with KDSS.
Good luck!
