Parents care for their children in different ways and there is no one way better than another provided the activities and care are child focused. Grandparents are bound to do things a different way. However, to avoid conflict sensitively tell them how you prefer things done and any major no's, and then trust that they follow your routine. If you trust your children with their grandparents then trust them to have the best interests of the grandchildren at heart. Instead of concentrating on small irritations look at the 'big ' picture and the added value grandparents bring to the children as well as your own life.
Children raised with lots of family interaction usually become better rounded individuals as the stress and strain as well as the enjoyment of exploration and adventure are shared by all. If , as a parent you want that 'first ' trip with your children , just get on with it instead of begrudging an enthusiastic grandparent for wanting to delight their grandchildren.
Most grandparents are more relaxed than parents as they choose to be with their grandchildren and can save their energies for those special occasions. Involving grandparents from an early age gives parents time to develop their own careers and enjoy social activities knowing their children are safe and nurtured. Look at grandparents as a positive influence instead of looking for all the negatives. Don't make this a power struggle but an experience that will be beneficial to your children and a positive influence. Past difficulties with grandparents should be in the past once you have discussed your basic child care preferences/routine with them. Whatever happens don't 'punish' your partner for the parents they have. Make the most of any help offered graciously and warmly, and so everyone has some enjoyment of the children.