A speed wrench is very useful removing and installing pieces with multiple screws like primary and cam covers.
It cuts down on the time to remove the screws drastically.

Speed Wrench 1)

Socket wrench extensions and adapters come in many sizes and aren't expensive.
Extensions can be doubled up for extra length in tight places. Add as many as you need. Good to stock up on.
Socket adapters allow you to use different drive wrenches on one socket.

Extensions are essential for changing lengths from the nut/bolt to the wrench.
Drive adapters allow you to use the same wrench with sockets made for different drive sizes.
You can buy adapters that accept screwdriver bits to allow you to remove/install/torque Phillips, Allen, Posidrive or other screw heads.
These are also helpful sometimes in giving more torque to remove stubborn screws.

Screwdriver bit adapter 2)

General socket extensions and drive adapters. 3)