I have had my gauge cluster out a few times. It is definitely a PITA, as there is just not a lot of slack in the harness. Very easy to scratch your dash and/or steering column while doing this if you're not careful, so put a towel or something over the column.

I am considering making a multiple pin connector and mini-harness to route all the lines through, in order to make it easier to work on the gauges in the future (as I have some gauge problems). Anyone done this already?

As far as the speedo goes, I have had good luck getting it out by feel without resorting to messing with the gauge cluster. Getting it back on is a little more tricky unless you have good "muscle memory" to know where to put the cable, but feeling around with the diagram in front of you may help.