For a 5-day trip, $2000 should be plenty, save the other 2 for your next trip.
My first suggestion is to post your exact travel dates (once set) in the Roll Call section of the board. Then make contact with a CRT who will be there at the same time, hopefully somebody who's been there before. Maybe they can show you around and show you how things work, it's much easier that way. It's customary to buy them a drink or two for their help. If you're a really nice guy, I'm sure a ZB session would be appreciated.
I agree, stay at Del Rey (or Presidente). I've never stayed there myself, but I can see how it would be easier for a first-timer to stay there.
Make sure you print out the monger's map, which has many of the places that the CRT guys like to frequent, Zona Blue, New Fantasy, Bar Idem.
Enjoy some of the restaurants in SJ. My fave place is La Esquina de Buenos Aires, an Argentinian steakhouse. Dinner for 2 is around $50. Soda Peru is a good choice for lunch 11am-4pm, just up the block from ZB.
Like Berk said, don't over-do-it with the drinking, for various reasons. #1 Safety, if your a stumbling drunk, you may get robbed or hurt. Make sure you are sober enough to be aware of what's going on around you and have your senses working. #2 Girls don't like to go with drunks, they prefer sober, non-stinky guys.
For a good two-girl experience, I recommend Zona Blue. With the VIP membership, you'll pay 21,000¢ ($42) per girl per hour. About $84 for a threesome for an hour. Pick one girl you like and let her pick the other girl, she'll pick someone she likes "working" with and you'll have a better time.
Days of the week matter little. There's action there everyday of the week. Del Rey is a 24/7 candy shop for men.
Try to check out one of the better strip clubs: Pantera Rosa or Kamur. Once you do, you will never step foot inside a US strip club again, like many of us. (I've been back once in the last 18 months, only because a buddy came to visit and wanted to go.) You can bang a hot stripper for 15-20 minutes in PR for like $30 or $75 for an hour at Kamur.
Maybe on day 3, right in the middle, do one of the day or half-day trips. It will give you a chance to do some fun things (I suggest Canopy tour aka zip lines, or ATV tour--both are very cool) and will give you a day to recharge your batteries.
Don't forget to eat and drink (water). Many newbies start phucking the moment they land and get hydrated and sick from lack of food and water.
Have fun.