Anyone else have experience doing such? I'm just starting, on a Deere 35D (a mini).  Anyone else have stories?

I don't know if in U.S.A. there are special driving licences to use this kind of equipement, but in Italy it is mandatory.
Honestly, i think it is safer for you take some driving exercises with qualified personnell than asking in a forum. 

However, i have an forklift driving license, i saw some bobcat and excavator where controls were similar.
It is mandatory to keep commands indicator clean and clearely visible, so when you locate brake, clutch and accelerator, you can try use all other controls.
Becareful of inertia and leverages involving physics on excavator, or you'll be in trouble.

I'm not sure if special licenses are required here either, but this was on private property anyway.  I wasn't so much asking how as just if anyone else has done the same before...
Haven't run it again since though...by now I'd have to start over at square one again. 

You may need a hydraulics license. They are required in my state whenever you operate anything with hydraulics on it IE excavator, bulldozer, backhoe, bobcat eta. 

I think the license is needed only if you operate it for the money (a business, as an employee,...), not on your enclosed private property.
In many states you do not need explicit license, but an equivalent training is required implicitly by work safety laws (practically it means the same). But when on your own, not public accessible property, you do not need anything.