If you are short on time the one ride to skip in my opinion is Custer state Park loop. See everything else first.

 

try to do your rides in a clockwise manner, that way you're always making right hand turns. i've seen bikes backed up for a mile trying to make a left turn.

 

Wow, seriously?

 

No, of course not. Bagga has issues😬

 

ev780 makes a good point. Blackhills area is stunningly beautiful and makes for awesome rides. but can get congested during the rally.(half million bikes in a small area) Ride what you can but you owe to yourself and the area to return during non rally times. the fall is great and will virtually have the place to yourself.
Needles, spearfish, iron mountain, nemo rd. Sheridan lake rd. to name afew.
there will be one page maps available outlining all these routes. grab one and head out.
Devils tower and its story is very cool but ride there is unremarkable and there is a charge to get up close to it. you get a great view from the entrance anyway.
Im doing Sturgis on 5th and 6th and then heading back in September , it just that good...and the hotels will be cheaper.

 

why would i lie? if you don't believe it, when you get there go counter clock wise.

 

The first time I rode to Sturgis was the first week of September, just after Labor Day. It was easily the most spiritual trip that I have ever taken. I have been back during the rally many times, and have always had a great time (even with all the Trailer Queens), but nothing will ever beat that trip.

 

Springtime is also awesome. The smells of everything in bloom in the area is amazing as you ride along.

 

Nemo Rd is one I haven't heard of before.

 

Don't have any advice but I'm jealous as hell. That run is a bucket list item for me regardless of how far from Sturgis I may live at the time. Currently, Houston TX so it'd be a hell of a ride. I'd love every minute of it though. Enjoy.