Planing a trip to WA state in May or early June. Want to visit Olympic, Mt. Rainier, and North Cascades National Parks. Plan to take 8 to 9 days. Is it possible/advisable to fly into Seattle and drive to the three parks in that time frame? Would early May or early June be best - weather wise? Places to stay near North Cascades? Best areas and places to stay near the other two? Any help would be greatly appreciated.