Can't recall if the battery and tray actually need to be removed or not, but I did anyway. Aside from that, it's pretty straightforward. Drain the system, undo the belt, wiring connector, line block, and unbolt the compressor. Remove from underneath.
The new drier will start absorbing moisture from the atmosphere immediately once the shipping caps are removed. I suppose there's no one-size-fits-all answer to how long you have to work, as it likely varies by climate. If you connect everything right away, it will only absorb moisture from inside the system. But to keep that saturation to an absolute minimum, you could leave the drier capped and wait to connect the lines until you're just about ready to evac & charge the system.
1995 Mustang GT (5.0), daily driver
1995 GMC C2500 (5.7), alternate daily driver