Quoted from SirMachismo:Try these guys:
https://arapahoerental.com/equipment-rentals-product/dolly---stair-climbing-(battery-power-escalera-sty/3081#
I haven’t rented from them but I called once to check and the Loveland location had these for rent. I think they rented in 4 hour blocks.
Arapahoe definitely still has that. However, Lethal is in Westminster and I have to believe any sizable tool rental company would be likely to also have one. Just get on the phone before you drive all the way up here and ask around.