Emlenton

Is there a trailer/boat launch near the Emlenton bridge, or is it just a small hand launch kinda place?

There is a concrete ramp under the bridge in Emlenton that was put in by the State.  Depending on the water level it can be tricky to use.  Water levels at 3' to 5' (at Franklin) would be ideal.  If the water is low you may need to wade into the water to assist the boat off/on the trailer.  The ramp is used regularly but I have never seen the area crowded with trucks and trailers.  If you are launching canoes you could also use the old ramp, just upstream, in front of the Emlenton IGA store.

With the water at 3' you can go up river about 1 1/2 miles to the first set of riffles.  Depending on your ambition, you could, walk/pull your boat thru the lower section and carefully work up thru the rest of the fast water.  Once up and thru, you have good water for about two miles until the next riffle at Blue Cliffs.  If you decide to trek up past the 1st riffle, stay to the left side, walk up the left shore line (about 50 yards), then at the top of the swiftest water, motor up the rest of the riffle by staying closer to the island then, cutting across to the left at the large rock on the left hand shore, then up thru the rest.  Always look ahead and avoid any V waves  created by an underwater rock.  It's not very hard if you take it slow and look ahead.  We did all that for 5 years before we went propless!  If you want to go past Blue Cliffs, stay to the right side and about a 1/3rd way from shore.  That is not a very difficult passage.
 
To go down stream: keep to the right side of the riffle under the  I -80 bridge and you should be all right.  Watch the area just past the bottom of the riffle as there are several flat rocks, that don't make waves, which could hit the prop.  After that you can go down stream past Parker.    
 
If you decide to fish the river from Emlenton.  Just across from the launch, and between the two bridges, is one of the best fishing areas along the river.

Not sure where the Little Scrubgrass is.  If it's the stream that flows under the old train bridges (where people camp) about 4 - 5 miles up river from Emlenton, thats' the Blue Cliff area.  You can get up to there if you navigate the first set of riffles and travel past Dodders Eddy and keep to the left of the island before the rapids.  The wide flats on the right side below the rapids gets very shallow.
 
As for the islands in the first riffles, stay to the left of the left island and travel as I described before.  About for the island on the right:, at 3' (river level) it is too shallow for a jet boat, or to pull your boat thru, if you follow the right side bank.  Don't go between the islands either, there is a shallow shoal seperating them that you will hit and then you also may not be able to get over to the left side bank North of the island.
 
You should be able to follow these directions on a satelite map image if the river was shallow enough to show the islands described.