A new-ish, well-maintained vehicle with new tires, fresh oil change etc, if it's left dormant & undriven untouched in a residential driveway for 1 year, will it be driveable after 1 yr?
Disconnect the battery. Don't leave gas in it. Make sure you've got proper antifreeze mixture in the coolant, if you're in an area where winters get freezing. And if you can, get a proper car cover.
Dont just disconnect the battery, take it out of the car and put it inside, on a battery tender if you can afford it. Put 1 or 2 of those closet dehumidifier tubs in it as a precaution against mould (especially if its been rainy in the leadup to storage) and if you're relatively smart with cars go into the fuse box and take out the fuse for the ecu/fuel pump so that if someone breaks into the house and finds the keys they cant just steal the car.
Also yes, DEFINITELY get a cover that fits well. Poor fitting covers can really damage the paint if they move around too much.
Even when disconnected, car batteries will self-discharge at a rate of 5-15% per month, so after an year, the battery will likely be drained completely.
@[email protected], what you could do is buy a solar trickle charger for your car battery, it'll help maintain the charge level. They're fairly cheap and good option, as long as your car (or panel) is exposed to sunlight.
Another issue is that your tyres will deflate. Typically tyres deflate around 1-3 PSI per month, or maybe more during summer or in hot climates. So by the end of the year, your tyres could be deflated to 3/4th their capacity. To solve this, you can get a portable air compressor, which can be powered by your car battery (which is hopefully still charged!).