New Ump - Rules Clarifications

[kyleflan]

I'm a new umpire and I'll be officiating my first solo game tomorrow. I've been reading up on some rules to make sure I have the best understanding possible. However, some questions have arose and I can't seem to find clear answers.

Obstruction. Obstruction is a DDB, I understand that. However, if a runner is obstructed between two bases, but decides to retreat to the initial base, are they still awarded the second base when play stops?

For instance - B1 hits a hard base hit to center field. F8 fields the ball and throws it to F6 waiting at 2B. B1 rounds 1B and when B1 does so, B1 collides with F3. B1 sees F6 with the ball and retreats to 1B. Does B1 get 1B or 2B?

Another obstruction question.
R1 on 2B R2 on 1B. B3 hits a ball to F1, on fielder's choice, F1 decides to throw to F6 at 2B. While running from 1B to 2B, R2 is obstructed by F4. After receiving the throw, F6 throws the ball to F5 who steps on the base, but does not tag R1 forgetting that the force was removed. Normally, R1 would be safe since the force was removed. But since R2 is going to be awarded 2B, is the force still in effect and ipso facto, R1 out?

Thanks,
Kyle