An often overlooked version of the vertical pass game is the 3 x 1 or 2 x 1 boundary “Read” involving the running back working into the boundary with a single wide receiver.
Field Side:
Whether a 3 x 1 or a 2 x 1 formation, you want to keep all skill players to that side in a two-high beater. For example, a Smash or Stick concept works well. (Insert Diagram 1 & 2)
Boundary WR & RB Alignment:
General alignment for the boundary WR is at the bottom of the numbers. (Insert Diagram 3) The running back will align at the inside leg of the offensive tackle to his side (The RB will never get to where he needs to be out of the “Pistol” or “Under Center”). This RB alignment will probably be slightly wider than normal so be careful not to give it away too much,too soon and be subtle. Perhaps think about aligning him at that spot on a few other plays like pass pro if you have him protecting the edge, etc.
Boundary WR “Read” Route Coaching Points:
The starting point is to get an inside release with a landmark of 10 yards downfield, 2 yards outside of the hash. Once the WR passes the second level defender, preferably over the top of him (LB or spun down safety), he will make his decision of whether he will continue up the field 2 yards outside the hash or work to the middle of the field, never giving up vertical push (Remember not to flatten out the route when working toward the middle).
( Diagram 4) Note: When you get into the red zone (+15 on in), it’s easiest to just tell the boundary WR to run to the near goal post. If on course of the route the second level defender disappears (blitzes), he should be looking for the ball as he runs his route.
RB “Read” Route Coaching Points:
The RB’s initial path will take him directly to where the WR lined up pre-snap working this course with his shoulders and eyes downfield and selling the vertical push. If the corner disappears, the RB should be looking for the ball after he crosses the line of scrimmage. Once the RB gets to that aiming point, he will then work upfield with his landmark at the bottom of the numbers. Once he gets to the determined depth, he will either hook it up or continue running up his vertical landmark (bottom of the numbers). Note: I have always used a depth of 8-10 yards for the RB on this play. Pass protection won’t allow for it being much deeper. The factor used to determine whether the RB hooks his route up back to the inside or continues to run up his vertical landmark is where the defender is when he gets to his assigned depth. 
If he has already passed up the defender (i.e., the corner sits in a cover 2 look or he “melted” or ran with the WR) then he will continue upfield. By continuing upfield in a hard cover 2 look, it will force the boundary safety to make a decision on covering the RB or the WR running the “Read” route
If the corner stays over the top of the RB, then he will hook it up at the desired depth. (Insert Diagram 7)
QB Reads On This Play:
As mentioned earlier, it’s best if a cover 2 beater is called to the field side so that if the deep middle of the field remains open when the ball is snapped (two-high safeties) then the QB will stay to the field with his reads. If the defense has only one-high safety when the ball is snapped, then the QB will work the boundary. His basic read is the WR to the RB. If the QB can “look” the deep safety over to the field, he should throw to the WR as he runs up the hash. If the safety isn’t biting on the QB’s eyes and sits in the deep middle, then the QB should know that the RB will have hooked up his route and is open.
A Few Other Possible Scenarios Regarding The Boundary Read For the QB:
1.) If it’s man-under coverage and the corner follows the WR, throw to the RB as he crosses the line of scrimmage.
2.) If the defense is playing a corner over the top with two-high safeties and running the OLB to the flat (quarters coverage), the QB has a field throw.
3.) If the outside Linebacker blitzes, the QB throws to the WR as he is running his “Read” route.
4.) If the defense is trying to “re-route” or “bang and carry” the WR using the OLB or sink safety to take his route away, consider using a field skill player to run to the boundary on a 5-yard shallow route (Insert Diagram 8) in a 3 x 1 formation.
If you are operating out of a two-back set and a 2 x 1 formation, consider using the second RB to run an option route by working 5 yards upfield and bursting to the boundary. (Insert Diagram 9) Or, have the RB hook it up at a depth of 5 yards to try to occupy the LB and free up the WR and allow the QB to make his normal boundary “Read” reads. In either of these scenarios, you must tell the RB to never hook it up. He must continue running his vertical route on either of these plays. If the RB hooked it up, he could potentially cloud up the picture for the QB and/or take the underneath route away by sitting with a defender in the way.
These two examples are also very good for man-under coverage when the LB matched up with the RB is a better athlete than your RB and is taking away his route.