Four of us are going on a Rick Steves' tour in August of 2019. The hotel that the tour starts at is all booked up (Buswells). So the question is where do we stay for the one night before the tour starts?
In July 2016, we stayed at the Jury's Inn on Parnell Street, and it was a decent hotel. The room was large and the service was friendly. It is about 1.6 km from your hotel but everything in Dublin is very walkable and taxis are easy to get. The Jury's Inn Christchurch is a little closer to your tour hotel. My husband and son stayed there once and really liked it. As I recall, it is more expensive and books up a little more quickly due to its location. We have also stayed at the Ashling Hotel - nice and on the tram line but even farther away. If you have Hilton points from business travel, the Hilton Garden Custom House is a good choice.
Enjoy your tour!
I assume you told the hotel you were joining the Rick Steves tour? I've never had an issue reserving an extra night before/after a RS tour, but I always inform the hotel when inquiring.
If you haven't already, contact the hotel directly. Your trip is over a year away, perhaps the hotel will put you on a waiting list in case someone cancels. In the meantime, you can make a reservation with free cancellation somewhere else as a backup. We stayed at Staunton's on the Green a few years ago and liked it very much. Good breakfast and the restaurant is open for dinner most nights. It's about half a mile from Buswells.
Dublin is a very expensive city for hotels.
We stayed at the Hilton Airport Hotel prior to leaving town in a rental car--for around $85. Restaurants are closeby, and a bus route can take you into the city center from there.