Unlike deer, squirrel meat really isnt affected by not gutting them when outside. Besides that, you're gonna boil them for at least an hour anyway. They're like chicken, theres not much you can do to ruin the flavor. As long as its moderately cool out, they should be fine for hours without skinning them. I don't gut mine after I shoot them, as its too much trouble and it doesn't affect the meat and any bacteria that grows is killed by the hours of boiling. If you don't plan on eating them for a while, just freeze them as you would any other meat.