Go Cruise Throttle Lock
I picked one of these up on a whim because I was doing a ride where I had 5+ hours of freeway riding round trip. I picked up the universal model that is adjustable because I couldn't find the diameter of our bars quickly on my phone. It's worth every bit of $30 to be able to stretch your throttle hand once in a while. I only used it when traffic was light but that was good enough to get me through the day. It was easy to install and only took me about 5 minutes to get the adjustment just right. It really felt odd to take my hand off of the throttle. I've never had a bike with any type of cruise control. The only issue that I had was that it's not that great unless the road is perfectly flat (duh..it's a throttle lock) and that's not really a big deal. You just have to give it a slight twist and then let go to maintain speed. It comes off quickly so I just threw it under the seat.