We did the 4 banger in my Frontier in and out in about 7 hours.
You can unbolt the engine from the trans, but those bolts are a bugger to get to. The crank angle sensor is also on the back of the block and needs to be disconnected and moved out of the way.
Power steering and AC should be able to be removed and laid to the side without having to disconnect everything.
On the engine mounts, they're not that bad to remove. Unbolt the frame side and loosen the nuts on the block. That should give it enough wiggle room to lift the motor out.
Also, pull the radiator and shroud...that gives you the room you need to pull the engine forward and then up and out.
What a great time to replace that 6th spark plug