Sure I have a few nuggets. I went through a couple cheap treadmills before I finally took the advice of another long-term treadmill desk user and bought a lifespan fitness:

https://www.lifespanfitness.com/workplace/treadmill-desks/tr...

It's an incredible sturdy and reliable treadmill. It has built in shock absorption and can autodetect your steps. Although I wear a clip-on fitbit to sync steps to my phone (wrist fitbit isnt going to work well to count steps since your hands will be typing or whatever).

I transitioned from a standing desk to a treadmill desk and was surprised that walking is actually much easier to sustain for long periods than standing. I started very slow. 1.2 mph. I gradually (and naturally) have made my way up to 2.4 mph.

If you get one, make sure to get good shoes! Something that a marathoner would use (e.g. Brooks, Asic, etc).

Getting a treadmill desk is among the best decisions I've ever made.