Sounds good, but working on a laptop constantly makes Forward Head Posture much more likely
Then again, I'm sitting on a computer with a wireless keyboard and mouse, in my living room chair, for many of the same reasons.
For shoulders and back I suggest getting a bow and start with archery, has done wonders for me and much more fun than lifting weights!
There is a good selection of tenkeyless keyboards available that will fit in your laptop bag (get one with a microusb port rather than a fixed cable, as strain relief for a fixed-cable that's getting shoved in a bag is challenging).
Then you just elevate your laptop (stack it on books, bags, whatever you have handy; I keep a few textbooks on my desk at home for this) and put the keyboard on your lap if sitting, or bar if standing. I wouldn't call it perfect, but it's mobile, affordable, and way better than a laptop alone IMO.
ahhh, the $800 monitor stand. (i do the same.)
No laptop in existence has a keyboard big enough for me. The smallest external keyboards I've used are probably larger than the largest laptop keyboards.
It's not about the size of the keys. It's about the location with respect to your shoulders. Having to angle your arms inwards is not a good idea.
Same for screen. If you're looking downwards, it's bad for your neck. Which is why I always use an external monitor.