The Elk Avenue project should be easy to complete. They've already had the ROW secure. In Google Earth you can literally see the ROW outline that makes room for a future diamond shaped exit. The same goes for Plato Road, Camelback Road and Osage Road. The intersection at Boren Blvd is an odd one. It looks almost like they carved out enough space for a couple of flyover ramps or something.
I'd like to know if the Northern extension of the Duncan bypass back into US-81 is a dead affair or just kind of hanging in limbo for the time being. I know ODOT was working on plans for the Duncan Bypass to dovetail back into US-81 South of Marlow. But I guess progress just kind of got suspended.
Regarding larger plans for US-81, I don't think it's nearly an important enough to justify upgrading into a freeway. I think just making a regular 4-lane route with limited access bypasses in key towns is going to be good enough.