given that the early roman republic is stretched out you'll probably have to be constantly in war however there are two tricks that should make the roleplying a bit more enjoyable and realistic

first secure an allicance with one of the gallic tribes (preferrable arverni). take all settlements north to your border and destroy every building in them and hand them out to your allies the arverni. that should keep them from coming at you and at the same time make sure that both you and the arverni are at war with the aedui. if the aedui manages to take any of the bordering settlements have a consul retake and give it back to the arverni never cease fire with the aedui, cuz once u do they might ceasedire with the arverni and it might happen that both would attach you.

now in spain take out carthage and have an allicance with the spanish tribe there. once the carthagians are out of spain keep the costal settlements as well as biakor and scum(somthing). eventually you'll have to deal with the spanish tribe so here is wht i do. blitz them take all town in spain destroy and keep the spanish conrnered at the north west. once u're done blitzing offer a huge sum of money plus all the settlements that you've conquered in spain to this tribe. that should keep them in check for sometime.