I went to Bhutan last year.
although there are no adventure activities to do. but here are few points to consider.. there are very few petrol pumps. so keep your bike full in main locations.
It can be rainy in June to August.
do tigers nest trek.
visit phobjikha valley (will be best part of your trip)
If you are taking your vehicle then keep in mind that RTO in Bhutan operates till 3pm.
Do not honk in Bhutan.
Try to stay with locals. you might want to use couchsurfing.com have a nice trip brother..
H, Travelers on tripoto never run short on suggestion and tips on travelling. There are few for Bhutan. You can check below attached cards giving suggestions on Bhutan. Please click on the card below to read their experience.