You could take a look at desiccant spark plugs as well.
Pretty much any fluids left in can go nasty, particularly with some of the weirder additives used in special versions. That said there's an offset against letting seals etc. dry out. so you may want to monitor and drain when you need to.
When it comes time to wake the vehicle back up, filler caps etc. can be insanely seized, so a bit of time spent now with some copperslip or similar will save you a bunch of heartache in the long run.
Note that this advice comes from waking vehicles back up, i've not had the experience of putting them to bed myself.