We are heading north from Galway through coastal Connemara and on to Donegal in early May for a week and would like to stay flexible with our itinerary. Can anyone tell us - will we have decent options if we call ahead a few days before at this time of year?
I'm not making you any guarantee, but if it were my trip, I'd go ahead with that plan. It may depend on your definition of "decent options." I also assume you're a couple and don't need any special type of room. Expect weekends to be busier, especially if the weather forecast is good.
Monday 6 May is a Bank Holiday here, so a lot of hotels will be busy the 4th/5th for weekend and family breaks.
Midweek you should be fine.
I've booked many times on the morning before I arrive and always been able to find a place. There are plenty of decent places all over Ireland that don't need much prior notice.
Probably the biggest exceptions to that are if there is a place you have your heart set on staying. If so, you should probably book that ahead.
I also book ahead for any fixed portions of my trip. I know when I'm flying in, so a place for that night saves mental wear and tear on my jet lag day. I know when I'm flying out so I'll plan to be near the airport the night before. Train tickets or booked activities can also "fix" a portion of your trip.