For SS/threshold intervals I go west county road 24 to county road 19, north on 19, and then make a loop out of it. There are a bunch of long roads with minimal stops out in that area. County road 24 is just north of county road 6 but it is less traveled, and not one single stop for about 5 miles.
For VO2 intervals I either go to dunkirk (segment is called dunkizzle). It is a 1.5 mile false flat. I will generally do the interval going north and rest going south. And @tnordberg is correct - there are some decent climbs (for MN) to do VO2 intervals coming out of the MN river valley. Off flying cloud drive there are a couple of hills you could probably turn into some decent VO2 intervals. Added bonus, Spring Road has a natural spring to fill up your water. It is always icy cold and most people will let you cut the line when they see how sweaty you are.
My two favorite roads for longer VO2 intervals are a couple of climbs coming out of chaska. Check out segments ‘Chaska Blvd over 212’ and ‘up shift creek’. I am a big fan of up shift creek. I only do it on my Cx bike though. The road is annoyingly rough for my road bike.