My husband and I are trying to plan a trip out west for the middle of next August lasting 30-35 days. We will start from southern Ohio and our main destination is Glacier National Park. I am thinking we need to head north at the beginning of the trip and return on a more southern route. We need advice on which routes will provide the most access to multiple national parks. Our drive time each day can average 6-8 hours, more if needed. Thanks in advance for any suggestions!