I was out there this weekend but probably won't be back until the IDPA match on Jan 2 with the holidays coming up. When they have matches the gates are open and spectators are welcome. That's a great time to visit the range, it lasts from around 9-12:30. Better yet, bring a pistol w/ 3 mags and 100 rounds of ammo and shoot the match. The IDPA club's annual Christmas party is going to be after that match too. Lunch, awards, and prizes for the shooters.
El Zono del Impacto, from what I understand, is a large piece of property/range that is member only. You are allowed to do just about anything, safe AND legal, where shooting is concerned.