ROI is abroad, I would prefer some decent behind closed doors games against decent opposition and hopefully the team would get more out that and be fit and ready for a new season.
Preparation for the new season should not be reliant on whether it's a good day out.
I think it would end in tears for some !Poland would be a great choice. I lived there a few years back and watched a few Cracovia games and keep an eye on Polish football.
Gdańsk for a coastal break or Krakow for a city break would be ideal. If fans went over there with the right attitude then then they would have a blast and would be really welcomed.
Cheap beer, accommodation and flights and plenty of interesting stuff to see and do. I think most of the top flight teams over there are Championship / 1st Div standard. I really miss living in Krakow, top place.