Pre tour place to stay

We are just starting the tour, stayed in Galway the first 3 days in Salt Hill, took the train to Ennis for the two days prior to the tour, and stayed at Glenomra B and B. It’s not a castle hotel but a nice BnB a few minutes walk into Ennis.

Dromoland Castle is the nicest and closest castle hotel to Ennis. A bit further, but fabulous, is Ashford Castle in Cong...north of Galway.

If the tour is staying at the Old Ground in Ennis I would suggest just staying there for the days before the tour. You can make day trips from there. It is a very nice hotel with helpful staff, good location and two excellent restaurants attached.
I can also recommend the Bunratty Castle Hotel. We stayed there for two nights at the end of the tour as we were flying back from Shannon. It is close to Ennis where the tour begins. The hotel is across the road from the folk park and a pretty cool castle. We really enjoyed spending a leisurely day walking through the folk park, looking at the exhibits, touring the castle, stopping at the pub in the park and shopping at the artisan shops scattered throughout the park.
https://www.bunrattycastlehotel.com/
https://www.shannonheritage.com/BunrattyCastleAndFolkPark/

Thank you all for your input, booked the Ashford Castle for 2 nights and then the Old Ground for the night before, our first RSE tour, looking forward to the experience