I don't like the blind corner in the initial pics that I modded (I thought it was @ 78th but background seem to indicate it is 79th) but the most dangerous one seems to me to at 78th.
I say this because it is so easy to come off of SW Pointer Rd with far too much speed. It really wouldn't hurt to have a "Bikes Yield to Peds" sign at every entrance.
Trimming back enough brush growth would be nice but PortlandMaps.org indicates that each of these blind corner spots is a currently occupied Single Family Residence meaning that the land owner is responsible. At the very least the W2-2 sign (Left Side T-Intersection warning sign)
could be placed in advance to tip off the inevitable speed racer that they are on the highway to the danger zone.
Section 9B.16 Intersection Warning Signs (W2 Series)
01 Intersection Warning (W2-1 through W2-5) signs (see Figure 9B-3) may be used on a roadway, street, or shared-use path in advance of an intersection to indicate the presence of an intersection and the possibility of turning or entering traffic.
02 When engineering judgment determines that the visibility of the intersection is limited on the shared-use path approach, Intersection Warning signs should be used.