Hotels: Casa Cayena, New Garden, Sosua Suites are all close to each other. Casa Cayena for quieter stay, New Garden for party atmosphere.
Don't bother with US, the rates are comparable. Why pay 2 exchange rates? Canadian accepted everywhere, just know your rates. Best exchange rates at Western Union and Banco Populaire, both within easy walking distance.
Everything is within easy reach from those hotels. Main street Pedro Clisante for the bars, DR Rosen for the hotels, beach at end of Clisante. Look on Google maps to get an idea.
Biggest problems would be girls trying to steal stuff in your room (lock valuables up), occasional pickpockets, guys that speak perfect english being your new friend (ex-drug dealers that will try for a free ride of drinks, food etc to show you around, not needed) and girls who are overly pushy (especially if they think you are new). Don't get stupid drunk and use common sense.
Casa Marina is an AI that discourages girls and make you pay for a guest pass. Not worth it.
When you book the hotel see if you can order airport pick up, some include it. 15 minute trip to town, taxi's charge $25US.
Beach is also a daytime pickup spot, except on Sundays when regular families go there. Playa Sosua, not Playa Alicia