We are a 10u travel team. She's an outstanding of and has the most game sense of anyone on the team. I've been playing a girl at SS that is serviceable but not great and I'm trying to recruit a player to play SS in the spring. Our other Columbia ach thinks we should play her there because of her game sense.
Without knowing all the details of the talent on your team, I think I would have the LH girl split time between 1st base and CF, that would be best for her long term develpment. I think you could argue that 1st base at the 10u travel level is just as important as SS for most teams. Her game sense can be used on ground balls that are hit near the 4-3 hole, I see it all the time where the 1st baseman comes to far off the bag on a ground ball in the 4-3 hole and the first baseman gets to far away from the bag to get back for the force out at the 10u level. At 1st base her game sense would come in handy on bunt defenses also. At 10u you also see right fielders throw out hitters at 1st more often because the outfielders don't play very deep, her game sense would be beneficial in that situation also. Honestly from my experience there are more balls hit to the 2nd baseman at the 10u level than any other position.