Generally, from what I've read, you want to let it run enough to have things get up to operating temperature and (among) other things cook off any water that's condensed in the oil, etc.

STABIL (the gas additive) will help prevent the gas becoming a lovely thick varnish (this can happen in a couple months..). Run the car for a bit after adding to get the mixture into the fuel lines, etc. Oh and fill the gas tank (water can't condense in the empty space that way).

Now, if it's just for a few weeks, that's one thing, but months and months, that's a horse of a different color.