First Trip to Dominican

Hi all, I've been a lurker on this site ever since I decided to take a trip to the Dominican Republic a while ago. I'm planning my trip with my boyfriend in May and we'll be staying at Casa Marina Beach & Reef Resort for 7 days. There's tons of things that I've already decided to do, but I want to try to get the best prices possible and was wondering if you guys could help me out with that. Here's the list I have so far. If there's anything else that you think I should see, please feel free to post and let me know!

Things to Do:

Horseback Riding
Cable Car to see Mt. Isabel de Torres
Diving, Snorkeling, Surfing, Waterskiing, Windsurfing, etc. (Pretty much all watersports)
White water rafting (by the way, anyone know how safe this is? Or if there's crocodiles/alligators in the water?!)
Ocean World (Anyone know how much the shark and stingray encounters cost or how much it costs for the video/pictures with the tigers and dolphins?)
27 Waterfalls
Canyoning and Cascading
Visiting the Gri-Gri Lagoon
Visiting the Blue Lagoon
Catamaran trip

I also have a couple other questions for you guys. I have been hearing conflicting reports about Dominican Pesos and US Dollars. Is it better to pay in Dominican money or US money? Personally it's probably easier for me to pay in US money that way I don't have to try to figure out the conversion, and carrying around so many pesos (33 for 1 dollar) would probably be inconvenient. What should I pay for with US and what should I pay for with pesos?

Cab drivers- Is it hard to find an English speaking cab driver, and how much will I generally end up paying? I know that it depends on the distance, but within the city?

Sorry for all the questions, just excited! Hope you guys can help me out!

Holly.

Great, thanks a lot! Do you know if the Shark/Stingray encounter is $80 each or for both? I thought the DVDs would be more expensive, so that's awesome too. I can't wait for the trip.

Oh, and Rocky you're right about my not having much time to laze around at the beach, but for my first time there, I have to see as much as possible. I'll hang around the pool or the beach in the evening if I have to. lol. I'm so happy there's no gators or crocs in the river. I'd be too terrified to go! Sharks I can handle, but anything that can follow me out of the water and eat me...No way!

Holly.

Rocky, it sounds like it's that way for a lot of things. From what I've been hearing, it's usually a lot cheaper to book everything in advance before we even get there rather than go through the hotel prices. I can't wait, I'm so excited!

Dominican/US Money

Rocky, I hope you don't mind my confirming this, but I read on Debbie's Travel Website about the Dominican and a few other places that the US dollar is accepted everywhere in the Dominican and that it is sometimes actually prefered? I would really rather pay in US money if at all possible, but would I be losing money if I did it that way? What about credit cards, debit cards and travellers checks? I don't want to bring a huge amount of cash with me, but I don't know how to bring all the money that I need with me. Can you give me some advice on this? Thanks.

Holly.