To add a few ideas intro the pot so to speak ....
When spannering, i have a supply of clear food bags,the ones that have the white bit on them that you can write on, are the best. Put stuff in them and label them saves a lot of 'hassle ' later on .....
Take a biro, make sure it works. (see above)
Take a cardboard box/crate, to put the above bags of bits in, believe me, it might seem daft, but nowt worse than having piles of 'stuff' in the way.
As said before, Digi camera ,not just to put pics on here, useful for reference as to how things fit.
Flask and some grub.