I don't know why you'd need to do preventative maintenance before storing a bike? If you mean before you ride it to Spain just make sure it's serviced and everything's OK - tyres etc.
Disconnect the battery when the bike's being stored, and put it on a battery maintainer (Optimate, C-Tek etc). Don't leave old, dirty oil in the engine - if it's old, change it before you leave the bike sitting.
Leave it with as little fuel in it as possible and then put super-unleaded in it from a can (don't ride it to the petrol station) before you use it again - petrol goes off with age and the less old petrol you have the better it'll be diluted by the fresh stuff. You can get petrol stabilised but I've never bothered with it.
Leave the bike on the centrestand so there's little weight on the tyres.