Whatever essentials you need, be it toothpaste, medicine, etc. make sure you purchase them as early as you can. The shops in Trim, with the exception of some of the petrol stations, close much earlier than the shops do in, say the U.S for example. There aren't any late night places like the ones that are common in the UK, much less any 24 hours stores you see in the U.S. Trim is a small traditional town that adheres to strict business hours. Even many of the restaurants close by 7pm, aside from the pubs of course. While bottled water, snacks, and basic medication are available at the petrol stations, you may want to get your essential shopping done during the daytime hours or else you'll need to drive closer to Dublin or wait until the following day.
Some of the country roads into and out of Trim can be hectic. There's not a lot of traffic on them, but they are winding and there are things that obstruct your views of the curves ahead, like foliage and homes/sheds, etc. If you're from a country where the driving takes place on the right side of the road, you'll want to take extra caution. Take your time and take the opportunity to get used to Irish driving, which is on the left side of the road. As the roads aren't too cluttered, its a good chance to learn the methods. When you're not comfortable, slow down , stray to the left, and let the car behind you pass you by. Local drivers in the rural areas tend to be more understanding of foreign drivers than those in the cities.