Yes, there will be a shuttle service which will pick up all attendees and drive them to the venue and also back to the hotel after the conclusion of the reception,
T-Mobile provides international data/texting plans for free, although the speed is reduced to during this time period. If needed you can purchase a faster data plan for $5 dollars a day through T-Mobile if needed. Verizon and AT&T currently do not have free international cellular plans, before you travel you may need to reach out to your cell phone provider so they can approve your phone for international use.
Some places (big and corporate companies, restaurants and stores) have card payment methods. Please check with your bank, since some of them will charge a % per transaction, and some of them will block the card for a period of time if you didn't notify them that you will travel.
You can rent a car (not suggested, drivers are more aggressive than in the USA and regulations are different) but you Uber app will work as it works in the USA. Also the location suggested to book your hotel offers a lot of places and activities that you can walk to it.