How to be in the best position-base mechanics

[DaveASA/FED]

I have two questions both deal with base mechanics in a two man system, both when you are behind the SS.
#1) R1 on 2nd hit to ss, how do you get inside the diamond to make that call at 1st? R1 is leading off, waiting to break to 3rd with the throw to 1st, ss is fielding the ball right next to you. I feel trapped and a lot of times end up making the call from only a couple of steps infront of or even with the base line. Is there something else I can do to get better position? I have never run infront of a runner that could advance does anyone recommend doing this? As that was another thought I had to run infront of them while they are holding and then move accross after the throw to get as good of an angle as possible at first.
#2) R1 on 2nd, R2 on 3rd 2 outs. Ball hit to ss who is playing up so I run in (as soon as speedy R1 passes me) ASSuming the throw to 1st for the 3rd out. YEP, you guessed it she went to 3rd where now I had to slam on the brakes (and a vehicle my size don't stop quick) and back pedal (as ss is where I would like to go) to get a look at 3rd, luckily R1 was quick so the play wasn't close and I could see it fine but if it would have been close I had TERRIBLE positioning to see a bang-bang play. SO, how do you position your self when there are 3 possible plays? On a play like that I guess I have assumed I'm going to first and headed into the diamond behind the pitcher's circle and then turned aroudn for a play at 2nd, or run parallel to 3rd if needed, but the SS was in the way on this play and it made me wonder if there was a better mechanic in this situation.