Transportation to and from the airport to Dublin city center

I actually have several transportation question. 
#1
I will be staying a Buswells's Hotel on Molesworth St.  Will I be able to access the Bus transport pick up to & from the Airport to near this hotel?
#2
How late does the DART line run if I wanted to visit Howth and stay for supper?  Where do I get on the DART station to do that?
#3 Are-the green hop on/off buses  the best way to navigate through City Center?  Is that the same as a red or blue tour bus?  Does the green bus offer tours or just transportation?
#4  Is it possible to arrange a Trinity college tour without going to the Book of Kells?  I noted that the Trinity college tour is only on Sat and Sundays in April.  We were thinking of seeing the college tour then go back to Book of Kells on Monday when it might be less crowded.  Sound like a good plan?
Thanks.
Kerry

Hi Kerry, 

How are you? Great to hear you are coming to visit Ireland. We have a blog post on how to get from Dublin airport to the city centre for our guests which we hope might answer some questions you have regarding transport around the city. We have bus numbers and information if you want to take a look at it. https://vagabondtoursofireland.com/how-do-i-get-from-dublin-airport-to-dublin-city-centre/. 

Hope this helps with the transport questions. 

Kind regards,

The Vagabond Team 

Hi Kerry, 

• Aircoach, Route 700 (Leopardstown Route). The nearest stop is Dublin City Centre - Kildare Street, which is adjacent to Molesworth Street where the hotel is located. 
  
• Dublin Bus, Airlink Route 757. From Dublin Airport, the nearest city centre stop is on Upper Merrion Street (opposite the Natural History Museum). Buswells Hotel is approximately a 10-minute walk from there.