You are right about the lack of HMI output on the RI r2. The small screen I have placed on a flexible stalk, from an old desk lamp which required fittings welded on. I mainly use it for outreach purposes, connected to a small projector that has an AV input and a portable screen. The r2 comes with an AV to USB device, at least it did when I bought mine, for video capture. I have used one minute exposures to capture video and stack in Registax. The results are not perfect, given that I have an alt-az mount, and field rotation can be a problem. Also there is some blurring at the far edges of the image, but perhaps a field flattener could correct that.
This was taken with RI r2, 10" GOTO dobsonian, 2" 2 x Barlow. 30s exposure.
http://imgur.com/a/EmLHd
There is a multitude of exposure settings available via the camera menu, the wired remote makes it pretty easy to scroll through all the settings, however, learning which settings are best for the object in view, and remembering them, was frustrating at first, I took notes and keep them with the kit. I haven't looked at the website in a while so maybe they have updated the info on the r2.
GOTO tracking accuracy: I have placed leveling feet on my dob base, I use a spirit level, do my alignment and then check its accuracy with SkySafari 5 with a Nexus-S Wifi hook up. Using my phone is quicker than the GOTO handset for locating objects.
Here's some live views from Youtube.
https://www.youtube.com/watch?v=GSUBnEk4kBE