I thought
The Marlins were constructing a state of the art facility (relative of course to where it's located) in .... I'm spacing the name but it's about 45 minutes N/NE of Santo Domingo.
Since the sale of the Marlins - John Henry, now the owner of the Red Sox - will be moving his new toy to this facility. I believe it's next to or near the Dodgers present facility - if anyone knows the name of where that is located.
Currently, the Sox are working out of S.D. near the Coast Guard (I believe it's the Coast Guard) facility, kind of near (over) the floating bridge.
From what I can glean, there isn't too much to see here - if visiting them is what you're thinking.
I know the Red Sox have practice from about 8 - 12, lunch, gym workouts til 4sh, then English training from 5-7.
Nothing too exciting.
If you want to see some local baseball (excluding the Winter League games - which I HIGHLY recommend, especially the championships in mid-january) I'd recommend going to Olympico Park in S.D. It's raw, scrimmage format ball, but I've been thoroughly entertained by it. It's aggressive (free-swinging, base stealing, pea-throwing fun) but raw. And it's free! Fridays at 10 am. usually.
I'll be the guy that looks like me.