I think I've got it down to a fine art now. The tricky bit is removing the old perko door closer (door closers are fitted here due to building regulations and stopping the path of a fire - not sure if you guys have the same rules in the states) these are fitted in the back edge of the door, sprung loaded and can be nasty if your finger gets caught. I've been using a pair of needle nosed mole grips (you'll get them back dad I promise) to hold the chain while I take out the screws (many have had to be drilled out due to the last carpenter rounding off the heads). When I release the mole grips it snaps together and makes you wince at the thought of your finger being in there (or at the height they're fitted at something worse)!
Then I fit a new overhead door closer (the setting out measurements are forever in my head 68mm, 105mm, 16m, 46mm) pretty easy things to fit if you read the instructions and use the templates - practice makes you faster.
Later I've got to drop back and repair all the doors where the perkos were, but access in a hotel can be a problem and it does hold me up a bit when rooms aren't available. Still the chamber maids are a good laugh and not many carpentry jobs you can wear a t-shirt in January.
Sorry if this is a boring post!