I doubt bugs would be a concern at any point in September. We go camping in Augusut up north and it's hit or miss on bugs depending on the year and rainfall.Thank you. 2nd week of Sept is the goal. Tricky line to walk wanting to he dun with the bugs and wanting warm(ish) weather. We're open to the whole state...we've never been so I know less than nothing about the place.
I've never heard anyone complain about the Ely area but I have no idea on mountain biking. It's about 9.5 hours from Omaha though, whereas Park Rapdis area is closer to 7 hours. Otter tail County is close to 6.