I will be in Dublin in early October for two days. I plan on visiting the usual sights, Guinness, Kilmainham Gaol, EPIC, Book of Kells, the Post Office etc. I will be staying at Jury's on Parnell.
For general getting about, would the Hop on Hop off bus be a good idea for transportation as it visits most, if not all of the sights?
Doubtless the HoHo bus is a good way to get around, but if it's merely transportation you are wanting then the LUAS tram network has to be the easiest way to get to all these locations, maybe coupled with the odd city bus on Dublin Bus.
https://www.luas.ie/
I used the HOHO bus on a trip to Dublin in around 2009. There was a new company operating at the time for a total of 3 HOHO companies, and I got a great deal for 72 hours since they were the "unknown" company. I used them for the initial orientation to the city, then for trips to Guiness, Kilmainham Gaol, Trinity College, the GPO, St. Patrick's and Christchurch Cathedrals. I used the bus in the evening to attend evensong at Christchurch and for transport to restaurants near their stops. Often, I was the only passenger on their bus, and so I got a personal overview of Dublin Georgian architecture with a young tour guide/architecture student and a discussion of Irish literature with another tour guide. He recommended a few authors I had never heard of (Sheridan Le Fanu, Niall Williams, Kevin Barry), whose books I've enjoyed immensely. I'd rate it a great experience, but I was also housesitting at the time, so I had plenty of time to spare. I generally use the LUAS or walk now, as the HOHO can be crowded and involve more waiting. But if you feel like trying it, go for it!
We used the HOHO that way recently in Dublin, worked well.
Personally, I embrace being a tourist. They drive on the left and it was easy to see everything in the city before choosing my first stop. Actually, I took the HOHO bus in every city visited - the Irish driver was hilarious. The best one. I tipped him all of my euros.
For my first trip to Dublin I used the hop-on hop-off bus and it was perfect for getting to the destinations (that you’ve listed) that I wanted to visit. For subsequent visits where visiting the highlights was no longer necessary I used the public transportation.
We used the Hop on Hop off bus that way. I was skeptical at first but it turned out to be a great way to visit some of the sites our first day in Dublin and gave us a good lay of the land for the rest of our stay.
For general getting about, would the Hop on Hop off bus be a good idea
for transportation as it visits most, if not all of the sights?
No. Hop on hop off-buses can be useful for sightseeing. But using them for transportation is a really bad idea. They take a very roundabout route through the city, so using them to get from A to B can take a long time. And it is also not cheap. A day pass costs €30, while you can travel as much as you like on city buses, trams and local trains in a day for €8.
