Hotel
Bally's is in a great central location along The Strip. We do not have a room block reserved. We recommend not trying to "save money" by staying at a cheaper hotel on The Strip (Stratosphere, Circus Circus, Rio) or in the Downtown/Fremont St area. From our experience, you will spend a lot of time and money on Uber to get to/from wedding events and popular attractions.
Flight
We recommend arriving in Vegas on Thursday or Friday. If you plan to leave on Monday (Memorial Day), be mindful of scheduling an early morning flight since the wedding is Sunday evening. Delta, Jet Blue, and Spirit are the airlines that offer non-stop flights from Boston to Vegas. There are no non-stop flights offered from airports in Maine or New Hampshire. There is no need to rent a car unless you plan on leaving the city.