The PW is capable, no one will argue otherwise. It's a hog on fuel though, especially when it is put to work. If you're already somewhat underwhelmed by the 4runner's fuel efficiency, I don't see you being happy with the PW's. I really encourage you to go read some of the magazine reviews and fuelly results...they about match up with what I've experienced and they're not too impressive. If you can live with that subpar fuel economy, the PW is indeed the best bang for your buck in terms of offroad capability.
The Tundra would be a good vehicle to pick up used. You can easily find Limited's for ~$32k, SR5's for less. If you're put off by the platform's age and upcoming generation refresh, then I don't see why you'd consider a PW or Ram 2500 given that its in the same scenario.
This is true when it’s comes to the 2018 and older 2500, the new facelift on the 2019 is quite the step up. At the end of the day the Ram and Super Duty are pretty much on par with one another now when it comes to overall features and power plants. Deep down I am a Ford guy, I have always favored them, but I enjoyed my PW experience and have very little bad to say about it.
If I am making the move solely to have the option of a build out in the bed then it probably makes more sense to have a HD with a payload over the 1500lbs the PW offers. I was pricing out a proper lift for the F250 last night and if I didn’t cut corners a Carli 4.5” will run me north of $7K before install and wheels and tires. I could get away with a 2.5” if I stick with 37’s but it won’t save me all that much. I have kicked around the idea of a 450 as well on super singles and while it’s a step up in overall build costs, it keeps me from having to regear and I’d be hard pressed to kill the axles even with 40’s.