I absolutely would not use a traditional car cover. When that cover gets wet, and sits against the paint - that's not a good situation at all. It's better to leave the paint and car uncovered where any snow/ice/rain can dry out. Covers are great at keeping sun off of a car - they are useless for keeping moisture off; it's worse for a car to sit under a wet cover than to be uncovered.
I agree with all the other suggestions - the thing I'd add - cover the inside of the windows to keep sun off the interior (tape/paper works fine); if it's all possible, put the battery in it, and turn the motor over every now and then. Pull the coil wire out - don't start it, just turn it over. Only start it if you can run it long enough to warm it completely up - boil off the condensate in the crankcase; clear out the condensate in the exhaust system. Cranking one briefly when it's cold absolutely fills up the exhaust system with water - not good for it to sit that way over the winter. So be sure it's good, hot and been driven for a while when you park it. Good luck.